Roberts Gemini 49
Bill Wright
only, which can sound very odd on old Beatles tracks. Is is right that these
radios do this? Is there any remedy?
Bill
Richard Evans
don't want to end up with the Pro DAB Police on my back.
Anyway don't suppose there is anything in any of the menus that can be
changed from stereo to mono.
Richard E.
DAB sounds worse than FM
news:Zu-dnTT3eq1eyRjX...@pipex.net
No idea, Bill. Probably best to contact Roberts, and if they don't
have a solution it sounds like it's a bit fooked.
--
Steve - www.savefm.org - stop the BBC bullies switching off FM
www.digitalradiotech.co.uk - digital radio news & info
"It is the sheer volume of online audio content available via
internet-connected devices which terrifies the UK radio industry. I
believe that broadband-delivered radio will explode in the years to
come, offering very local, unregulated content, as well as opening a
window to the radio stations of the world." - from the Myers Report
Bill Wright
"DAB sounds worse than FM" <dab...@fooked.com> wrote in message
news:7elp80F...@mid.individual.net...
> "Bill Wright" <insertmybu...@f2s.com> wrote in message
> news:Zu-dnTT3eq1eyRjX...@pipex.net
>> Nephew complains that his Roberts Gemini 49 reproduces one stereo channel
>> only, which can sound very odd on old Beatles tracks. Is is right that
>> these radios do this? Is there any remedy?
>
>
> No idea, Bill. Probably best to contact Roberts, and if they don't have a
> solution it sounds like it's a bit fooked.
I was wondering whether he has a faulty product, or whether the product is
faulty. If you get my drift. Surely Roberts wouldn't bring out a radio that
only fed one audio channel to the speaker. Would they?
Bill
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7elp80F...@mid.individual.net...
>> "Bill Wright" <insertmybu...@f2s.com> wrote in message
>> news:Zu-dnTT3eq1eyRjX...@pipex.net
>>> Nephew complains that his Roberts Gemini 49 reproduces one stereo
>>> channel only, which can sound very odd on old Beatles tracks. Is
>>> is
>>> right that these radios do this? Is there any remedy?
>>
>>
>> No idea, Bill. Probably best to contact Roberts, and if they don't
>> have a
>> solution it sounds like it's a bit fooked.
>
> I was wondering whether he has a faulty product, or whether the
> product is
> faulty. If you get my drift.
I think so! I'm not aware of there being any inherent problems with
any DAB radios made by the better manufacturers like Roberts, so I'd
personally expect it to be a faulty product. ;-)
> Surely Roberts wouldn't bring out a radio
> that only fed one audio channel to the speaker. Would they?
Nah, I doubt it. You'd expect something like that from
Bush/Alba/Goodmans et al, but not Roberts.
Bill Wright
>> that only fed one audio channel to the speaker. Would they?
>
>
> Nah, I doubt it. You'd expect something like that from Bush/Alba/Goodmans
> et al, but not Roberts.
I wonder what happens in the radio to combine the two audio channels? Does
the decoder produce two seperate analogue audio signals that are then
combined, or what? Or could it be that the decoder is programmed to produce
a mono output that is the sum of the two stereo channels?
Bill
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7eo4tbF...@mid.individual.net...
>> "Bill Wright" <insertmybu...@f2s.com> wrote in message
>> news:mK2dnasvdfJHbxjX...@pipex.net
>>> Surely Roberts wouldn't bring out a radio
>>> that only fed one audio channel to the speaker. Would they?
>>
>>
>> Nah, I doubt it. You'd expect something like that from
>> Bush/Alba/Goodmans
>> et al, but not Roberts.
>
> I wonder what happens in the radio to combine the two audio
> channels? Does
> the decoder produce two seperate analogue audio signals that are
> then
> combined, or what?
The MP2 decoder will produce the left and right channel signals whilst
still in the digital domain, and those signals will be separately
converted to analogue.
> Or could it be that the decoder is programmed to
> produce a mono output that is the sum of the two stereo channels?
No, it wouldn't be done like that because of the way the MP2 decoder
produces the separate channels, so it sounds like there's a fault with
the radio itself.
jamie powell
>
>> Or could it be that the decoder is programmed to
>> produce a mono output that is the sum of the two stereo channels?
>
>
> No, it wouldn't be done like that because of the way the MP2 decoder
> produces the separate channels, so it sounds like there's a fault with the
> radio itself.
You could easily downmix the stereo signal to mono within the digital domain
and feed it to a single-channel DAC to feed a mono amplifier and speaker.
I agree that this won't be the case on this particular radio though, in view
of its stereo output via headphone socket (in fact I think all current DAB
radios with mono speakers feature stereo outputs).
There should just be a simple combining of the two channels in the analogue
domain before they reach the speaker.
It could be that the headphone socket is faulty, and is continuing to mute
one channel even when no headphones are inserted. I have an old portable FM
radio which does this - it's solved by inserting and removing the headphone
plug a few times.
DAB sounds worse than FM
news:h695cf$pu5$1...@aioe.org
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7epvacF...@mid.individual.net...
>>
>>> Or could it be that the decoder is programmed to
>>> produce a mono output that is the sum of the two stereo channels?
>>
>>
>> No, it wouldn't be done like that because of the way the MP2
>> decoder
>> produces the separate channels, so it sounds like there's a fault
>> with
>> the radio itself.
>
> You could easily downmix the stereo signal to mono within the
> digital
> domain and feed it to a single-channel DAC to feed a mono amplifier
> and
> speaker.
I thought Bill meant that the radio had 2 speakers, but I've just
looked at a picture of one and it's actually a mono radio. So ignore
what I said above.
Bill Wright
> produces the separate channels, so it sounds like there's a fault with the
> radio itself.
I'll tell him then. Although there's still the question of whether all these
radios have the fault or just his.
Bill
DAB sounds worse than FM
Actually, although I previously said that Roberts radios should be
fault-free, I've reviewed a couple of Roberts DAB radios which had a
single speaker but for FM they were set by default to receive in
stereo mode, so they required higher SNR to receive a hiss-free
signal. And when I actually contacted Roberts about this via their PR
company, the cheeky bugger who replied tried to suggest that this was
by design. Er, incompetent design then, pal.
So it's best not to rule out that all radios suffer from this fault.
Bill Wright
> "jamie powell" <jami...@excite.com> wrote in message
> news:h695cf$pu5$1...@aioe.org
>> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
>> news:7epvacF...@mid.individual.net...
>>>
>>>> Or could it be that the decoder is programmed to
>>>> produce a mono output that is the sum of the two stereo channels?
>>>
>>>
>>> No, it wouldn't be done like that because of the way the MP2 decoder
>>> produces the separate channels, so it sounds like there's a fault with
>>> the radio itself.
>>
>> You could easily downmix the stereo signal to mono within the digital
>> domain and feed it to a single-channel DAC to feed a mono amplifier and
>> speaker.
>
>
> I thought Bill meant that the radio had 2 speakers, but I've just looked
> at a picture of one and it's actually a mono radio. So ignore what I said
> above.
Righto.
Bill
jamie powell
>
> Actually, although I previously said that Roberts radios should be
> fault-free, I've reviewed a couple of Roberts DAB radios which had a
> single speaker but for FM they were set by default to receive in stereo
> mode, so they required higher SNR to receive a hiss-free signal.
oh no! not this again! You were made a complete fool of because you didn't
even know that FM stereo hiss disappears when the two channels are combined
into mono, remember?
Don't wriggle on this, else I'll post google links of our exchanges for all
to see :p
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7er516F...@mid.individual.net...
>>
>> Actually, although I previously said that Roberts radios should be
>> fault-free, I've reviewed a couple of Roberts DAB radios which had
>> a
>> single speaker but for FM they were set by default to receive in
>> stereo
>> mode, so they required higher SNR to receive a hiss-free signal.
>
> oh no! not this again! You were made a complete fool of because you
> didn't
> even know that FM stereo hiss disappears when the two channels are
> combined into mono, remember?
Considering that I've owned an FM tuner with a mono button that
suppresses hiss for more years than your scrawny arse has been alive,
I fink I might have been aware of the effect that pressing the mono
button has. Duh.
> Don't wriggle on this, else I'll post google links of our exchanges
> for
> all to see :p
Oh, feel free to. I vaguely recall that I wasn't aware of one of the
bleeding ways you can combine stereo channels together to get the mono
signal - it wasn't anything as basic as me not realising that
switching to mono suppresses hiss, or me not knowing why switching to
mono suppresses hiss. So YMMV a great deal.
jamie powell
> "jamie powell" <jami...@excite.com> wrote in message
> news:h6a703$49c$1...@aioe.org
>> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
>> news:7er516F...@mid.individual.net...
>>>
>>> Actually, although I previously said that Roberts radios should be
>>> fault-free, I've reviewed a couple of Roberts DAB radios which had a
>>> single speaker but for FM they were set by default to receive in stereo
>>> mode, so they required higher SNR to receive a hiss-free signal.
>>
>> oh no! not this again! You were made a complete fool of because you
>> didn't
>> even know that FM stereo hiss disappears when the two channels are
>> combined into mono, remember?
>
>
> Considering that I've owned an FM tuner with a mono button that suppresses
> hiss for more years than your scrawny arse has been alive, I fink I might
> have been aware of the effect that pressing the mono button has. Duh.
>
>
>> Don't wriggle on this, else I'll post google links of our exchanges for
>> all to see :p
>
>
> Oh, feel free to. I vaguely recall that I wasn't aware of one of the
> bleeding ways you can combine stereo channels together to get the mono
> signal - it wasn't anything as basic as me not realising that switching to
> mono suppresses hiss, or me not knowing why switching to mono suppresses
> hiss. So YMMV a great deal.
*lol*
would anyone else care to do the honours, or shall I? :)
DAB sounds worse than FM
jamie powell
Very well. Here's some of your quackery for all to see. It even includes
some of your GCSE-level faux-equations:
http://groups.google.com/group/alt.radio.digital/msg/598302bf42cf5f02
DAB sounds worse than FM
In case you've forgotten, you claimed the following:
"You were made a complete fool of because you didn't
even know that FM stereo hiss disappears when the two channels are
combined
into mono, remember?"
Please provide a quote from that post or any other post on that thread
which suggests that I didn't know that switching to mono suppressed
the hiss. As I've already said, I knew switching from stereo to mono
on FM suppressed hiss before your mummy gave birth to the snivelling
whinging little git that is Jimmy Powell.
Richard Evans
>
> Very well. Here's some of your quackery for all to see. It even includes
> some of your GCSE-level faux-equations:
> http://groups.google.com/group/alt.radio.digital/msg/598302bf42cf5f02
It seems that the mistake here was thinking that there were 2
independent sources of random noise, when in reality they are 2 opposite
copies of the same random noise source.
Richard E.
jamie powell
>>
>> Very well. Here's some of your quackery for all to see. It even includes
>> some of your GCSE-level faux-equations:
>> http://groups.google.com/group/alt.radio.digital/msg/598302bf42cf5f02
>
>
> In case you've forgotten, you claimed the following:
>
> "You were made a complete fool of because you didn't
> even know that FM stereo hiss disappears when the two channels are
> combined
> into mono, remember?"
>
> Please provide a quote from that post or any other post on that thread
> which suggests that I didn't know that switching to mono suppressed the
> hiss. As I've already said, I knew switching from stereo to mono on FM
> suppressed hiss before your mummy gave birth to the snivelling whinging
> little git that is Jimmy Powell.
It's *jamie* powell, and I neither whinge nor snivell.
All the info is in the above linked post - I'm saying it cancels out when
the two channels are combined, and you're saying - with the 'aid' of your
wannabee-einstein equations - that it doesn't.
Richard Evans
>
>
> In case you've forgotten, you claimed the following:
>
> "You were made a complete fool of because you didn't
> even know that FM stereo hiss disappears when the two channels are
> combined
> into mono, remember?"
>
> Please provide a quote from that post or any other post on that thread
> which suggests that I didn't know that switching to mono suppressed
> the hiss. As I've already said, I knew switching from stereo to mono
> on FM suppressed hiss before your mummy gave birth to the snivelling
> whinging little git that is Jimmy Powell.
As I remember it, the discussion started because, you were talking about
a radio with only one speaker, which wrongly defaulted to stereo FM
reception instead of mono, and generated more noise as a result. I
thought this sounded strange, as I was assuming that the radio would add
the left and right channels together, so how come the stereo hiss was
not cancelled out. You then started saying that adding the two channels
together would not cancel the hiss, and refused to believe that the
stereo hiss could be cancelled in this way.
In the post that Jamie quoted, you came up with some maths to prove your
point of view. Looking at it again now, it seems your mistake was in
thinking that the 2 channels contained random noise generated
independently from each other, when in reality they contain 2 opposite
copies of the same random noise.
Richard E.
Christopher Hunter
Actually, it's not "cancelling out" - when you switch to mono, you're
reducing the received bandwidth by a factor of over 4:1. The poorly
designed Zenith-GE stereo system (used because it maintained
compatibility with mono) requires a bandwidth to ~70 kHz (the difference
signal is transmitted as DSSC, thereby wasting bandwidth), whereas mono
only goes to 15 kHz. As the receiver selectivity increases, the signal
to noise ratio improves.
Transmission of stereo requires four times the transmitter power for the
same S/N ratio as mono.
This provides another reason that the "powers that be" want to migrate to
DAB - the FM transmitters are relatively high powered, and require a lot
of expensive electricity. The DAB transmitters by comparison are /much/
lower powered, and with modern transmitter design methods, their
efficiency is very high.
jamie powell
"Christopher Hunter" <Christoph...@invalid.inv> wrote in message
news:7evb8eF...@mid.individual.net...
> On Tue, 18 Aug 2009 02:19:22 +0100, jamie powell wrote:
>>
> Actually, it's not "cancelling out" - when you switch to mono, you're
> reducing the received bandwidth by a factor of over 4:1. The poorly
> designed Zenith-GE stereo system (used because it maintained
> compatibility with mono) requires a bandwidth to ~70 kHz (the difference
> signal is transmitted as DSSC, thereby wasting bandwidth), whereas mono
> only goes to 15 kHz. As the receiver selectivity increases, the signal
> to noise ratio improves.
>
> Transmission of stereo requires four times the transmitter power for the
> same S/N ratio as mono.
The issue being debated was the amount of audible hiss when the FM tuner is
*set to stereo mode*, and its L and R outputs are subsequently combined into
mono, versus what happens when the FM tuner is *set to mono mode* in the
same situation.
The answer of course, is that in both these scenarios, the amount of audible
hiss is exactly the same.
I'd invite you to read the entire thread - it's right here:
http://groups.google.com/group/alt.radio.digital/browse_frm/thread/7b0b386a2231e818
tony sayer
<Christoph...@invalid.inv> scribeth thus
Can you explain why its more expensive to transmit on Dab tho?..
--
Tony Sayer
Christopher Hunter
>>Transmission of stereo requires four times the transmitter power for the
>>same S/N ratio as mono.
>>
>>This provides another reason that the "powers that be" want to migrate
>>to DAB - the FM transmitters are relatively high powered, and require a
>>lot of expensive electricity. The DAB transmitters by comparison are
>>/much/ lower powered, and with modern transmitter design methods, their
>>efficiency is very high.
>
> Can you explain why its more expensive to transmit on Dab tho?..
.. because it's a "closed shop" and the "service providers" can charge
whatever the hell they like. Radioscrape (for example) are a bunch of
clueless losers who're making oodles of money from the broadcasters
because they were given (effectively) a monopoly by the infinitely stupid
OFCOM.
I'm seriously tempted to add another multiplex in my area, and offer /
very/ cheap carriage to any broadcaster that wants to use it....
bolta...@yahoo.co.uk
"jamie powell" <jami...@excite.com> wrote:
>The issue being debated was the amount of audible hiss when the FM tuner is
>*set to stereo mode*, and its L and R outputs are subsequently combined into
>mono, versus what happens when the FM tuner is *set to mono mode* in the
>same situation.
>
>The answer of course, is that in both these scenarios, the amount of audible
>hiss is exactly the same.
You're assuming the hissing from the L & R channels will be exact opposites in
phase and cancel each other out when recombined. I'm still not convinced
that'll happen because even the smallest difference in delay between one
channel processing or the other due to slightly difference analogue component
tolerances will prevent this happening.
Of course if some of this hiss comes from some part of the stereo decoder
itself then a recombined stereo signal will never sound the same as the pure
mono one no matter what.
B2003
jamie powell
<bolta...@yahoo.co.uk> wrote in message news:h6ee7j$uu5$1...@aioe.org...
> On Tue, 18 Aug 2009 15:14:16 +0100
> "jamie powell" <jami...@excite.com> wrote:
>>The issue being debated was the amount of audible hiss when the FM tuner
>>is
>>*set to stereo mode*, and its L and R outputs are subsequently combined
>>into
>>mono, versus what happens when the FM tuner is *set to mono mode* in the
>>same situation.
>>
>>The answer of course, is that in both these scenarios, the amount of
>>audible
>>hiss is exactly the same.
>
> You're assuming the hissing from the L & R channels will be exact
> opposites in
> phase and cancel each other out when recombined.
They are and they do.
> I'm still not convinced
> that'll happen because even the smallest difference in delay between one
> channel processing or the other due to slightly difference analogue
> component
> tolerances will prevent this happening.
No delays are introduced within the receiver. If they were, the
reconstruction of a stereo signal wouldn't work at all, and the audio output
would sound very odd, with or without hiss.
> Of course if some of this hiss comes from some part of the stereo decoder
> itself then a recombined stereo signal will never sound the same as the
> pure
> mono one no matter what.
No hiss comes from the stereo decoder hardware itself, and even if it did,
that'd get cancelled out too.
bolta...@yahoo.co.uk
"jamie powell" <jami...@excite.com> wrote:
>> I'm still not convinced
>> that'll happen because even the smallest difference in delay between one
>> channel processing or the other due to slightly difference analogue
>> component
>> tolerances will prevent this happening.
>
>No delays are introduced within the receiver. If they were, the
>reconstruction of a stereo signal wouldn't work at all, and the audio output
>would sound very odd, with or without hiss.
Depends how out of phase the outputs were. A small fraction of a wavelength
phase difference will make bugger all difference to the stereo image but it'll
make a big difference to any perceived hiss when the channels are recombined.
>> Of course if some of this hiss comes from some part of the stereo decoder
>> itself then a recombined stereo signal will never sound the same as the
>> pure
>> mono one no matter what.
>
>No hiss comes from the stereo decoder hardware itself, and even if it did,
Well it would be the first piece of analogue audoi circuitry that didn't create
hiss in that case.
>that'd get cancelled out too.
Not necessarily if the components decoding the left channel produced
difference noise to those decoding the right.
B2003
DAB sounds worse than FM
Another idiotic comment from The Idiot. DAB receivers consume far more
power than FM receivers, so multiply that by the number of receivers
in-use at any given time and DAB consumes far more power than FM
overall.
> The DAB transmitters by comparison are /much/
> lower powered, and with modern transmitter design methods, their
> efficiency is very high.
Idiot.
DAB sounds worse than FM
Wrong. If there's some correlation between the L and R channels, and
there usually is a high correlation, then the L+R signal will
obviously have a higher power than the L-R signal. Receiver noise is
Gaussian, or in other words the noise is flat across the bandwidth,
therefore the SNR for the L+R is higher than the SNR for the L-R.
Therefore, the increase in SNR by switching from stereo to mono is
greater than the 6 dB you imply by merely reducing the bandwidth by a
factor of 4.
Here was me thinking he might actually understand analogue radio
considering that he's a retired broadcast engineer, so he'll have
spent his life working with analogue, but he doesn't even understand
that!
DAB sounds worse than FM
That's obviously bullshit, because when you're listening to a slightly
hissy stereo station and you switch to mono the hiss disappears.
Therefore the amount of audible hiss has obviously been reduced.
hwh
> Wrong. If there's some correlation between the L and R channels, and
> there usually is a high correlation, then the L+R signal will
> obviously have a higher power than the L-R signal. Receiver noise is
> Gaussian, or in other words the noise is flat across the bandwidth,
> therefore the SNR for the L+R is higher than the SNR for the L-R.
> Therefore, the increase in SNR by switching from stereo to mono is
> greater than the 6 dB you imply by merely reducing the bandwidth by a
> factor of 4.
Come on guys, simply look at various receiver specs to see it is more
than 10 dB. 50 kW can be reduced to about 4 kW when you switch off the
stereo.
gr, hwh
DAB sounds worse than FM
> <bolta...@yahoo.co.uk> wrote in message
> news:h6ee7j$uu5$1...@aioe.org...
>> On Tue, 18 Aug 2009 15:14:16 +0100
>> "jamie powell" <jami...@excite.com> wrote:
>>> The issue being debated was the amount of audible hiss when the FM
>>> tuner
>>> is
>>> *set to stereo mode*, and its L and R outputs are subsequently
>>> combined
>>> into
>>> mono, versus what happens when the FM tuner is *set to mono mode*
>>> in
>>> the same situation.
>>>
>>> The answer of course, is that in both these scenarios, the amount
>>> of
>>> audible
>>> hiss is exactly the same.
>>
>> You're assuming the hissing from the L & R channels will be exact
>> opposites in
>> phase and cancel each other out when recombined.
>
> They are and they do.
The signals that are used to reconstruct the Left and Right stereo
channels are as follows:
L + R and L - R
See:
http://upload.wikimedia.org/wikipedia/commons/c/cd/RDS_vs_DirectBand_FM-spectrum2.svg
But these signals have noise added by the RF front-end, so in reality
the signals used to reconstruct the Left and Right channels are:
L + R + n1
L - R + n2
where n1 and n2 are different noise signals (the bandwidth is
different, so the noise is obviously different as well) added to the
sum and difference signals respectively.
The Left and Right stereo channels are reconstructed as follows:
Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2
The noise on the Left and Right channels is therefore (n1 + n2)/2.
In comparison, the noise added to the mono L + R signal is just n1
(see above).
n1 != (n1 + n2)/2
QED.
DAB sounds worse than FM
message
> On Tue, 18 Aug 2009 15:19:22 +0100, tony sayer wrote:
>
>>> Transmission of stereo requires four times the transmitter power
>>> for the
>>> same S/N ratio as mono.
>>>
>>> This provides another reason that the "powers that be" want to
>>> migrate
>>> to DAB - the FM transmitters are relatively high powered, and
>>> require a
>>> lot of expensive electricity. The DAB transmitters by comparison
>>> are
>>> /much/ lower powered, and with modern transmitter design methods,
>>> their
>>> efficiency is very high.
>>
>> Can you explain why its more expensive to transmit on Dab tho?..
>
> .. because it's a "closed shop" and the "service providers" can
> charge
> whatever the hell they like. Radioscrape (for example) are a bunch
> of
> clueless losers who're making oodles of money from the broadcasters
> because they were given (effectively) a monopoly by the infinitely
> stupid
> OFCOM.
Hahahahahahahahahhahahaahaahhahahahahaahahahahahahaahaha!!!!!!!!
He's confused Radioscape (a DAB receiver module and DAB multiplex
equipment manufacturer) with Arqiva (a transmission provider).
The man's a clueless idiot.
> I'm seriously tempted to add another multiplex in my area, and offer
> /
> very/ cheap carriage to any broadcaster that wants to use it....
You? You struggle to put your trousers and your underpants on in the
right order, so don't try to suggest that you could set up your own
multiplex operating business from scratch.
DAB sounds worse than FM
news:4a8ad24b$0$187$e4fe...@news.xs4all.nl
I said that the difference is more than the 6 dB that Christopher "The
Idiot" Hunter implied when he said the bandwidth is reduced by a
factor of 4.
Christopher Hunter
>> Transmission of stereo requires four times the transmitter power for
>> the same S/N ratio as mono.
>>
>> This provides another reason that the "powers that be" want to migrate
>> to DAB - the FM transmitters are relatively high powered, and require a
>> lot of expensive electricity.
>
>
> Another idiotic comment from The Idiot. DAB receivers consume far more
> power than FM receivers, so multiply that by the number of receivers
> in-use at any given time and DAB consumes far more power than FM
> overall.
Right. I'll reply to this moron just once, then he can FOAD:
The normal transmitter power of a DAB transmitter is (typically) two to
three orders of magnitude less than a Band II regional transmitter.
You do understand what that means, don't you? No. I thought not.
In simple terms, so you can follow:
It's going to take a hell of a lot of DAB transmitters and even more of
these supposedly power-hungry receivers to come even close to the power
budget of a /single/ Band II FM transmitter.
What a clueless fool.
On your stupid Arqiva jibe:
http://www.radioscape.com/ might actually help you to understand what's
going on, though it's unlikely you'd understand or choose to deliberately
misunderstand what's written there. Who do you think Arqiva buy their
coders from?
Next:
You obviously have no actual concept of received bandwidth - the reason
for the relative noisiness of a stereo FM signal when compared to a mono
one is purely determined by the received bandwidth. The required
bandwidth for Zenith-GE stereo is slightly more than four times that
required for mono. Add in the other sub-carriers - the RDS, the stereo
pilot and the control signals (which, like it or not, affect the noise
content), and the overall noise floor on a good FM path is actually
rather poor.
You're probably the kind of buffoon that still insists on listening to
analogue tape and vinyl records, and fondly believes that the compact
cassette is an unsurpassed medium because "it can't get scratched". In
that case, the noise inherent in stereo broadcasting will make you feel
right at home. It's what you've come to expect. However, you're
listening to a digital source (mostly CD or automated hard-disk based
players) that are having their inherently excellent noise floor
compromised by an ineffective FM broadcast path.
"Halfwit" overestimates your intellect by a factor of at least two.
You have NO IDEA what you're blathering on about, and invariably jump
into every thread with your two club feet. You have no clue about
anything at all, and obviously are deluded into thinking that you have
some axe to grind.
Your best bet is to take down your silly little website, and to go back
to listening to your substandard radio, and stop bothering the grown-ups.
Now - back to work... (unlike you, the unemployable cretin that I'm
replying to).
jamie powell
This really shows how thick you actually are, because you were told quite
clearly last year by a great many people what the situation was, and you
still haven't learned a thing.
This is also the type of mentality that prevents people like you from ever
getting any degrees.
Do you in all seriousness still deny that "n2" (as you call it) is
180degrees out of phase between the two stereo channels?
<Sesame Street voice>
You *add* the difference signal AND noise present on it, to recreate the
left channel.
You *subtract* the difference signal AND noise present on it, to recreate
the right channel.
</Sesame Street voice>
The final + in your quack equation for the right channel above should
actually be a minus.
And since it's used so frivolously these days *clears throat*:
QED.
jamie powell
> "jamie powell" <jami...@excite.com> wrote in message
> news:h6ecvm$thr$1...@aioe.org
>> "Christopher Hunter" <Christoph...@invalid.inv> wrote in message
>> news:7evb8eF...@mid.individual.net...
>>> On Tue, 18 Aug 2009 02:19:22 +0100, jamie powell wrote:
>>>>
>>> Actually, it's not "cancelling out" - when you switch to mono, you're
>>> reducing the received bandwidth by a factor of over 4:1. The poorly
>>> designed Zenith-GE stereo system (used because it maintained
>>> compatibility with mono) requires a bandwidth to ~70 kHz (the difference
>>> signal is transmitted as DSSC, thereby wasting bandwidth), whereas mono
>>> only goes to 15 kHz. As the receiver selectivity increases, the signal
>>> to noise ratio improves.
>>>
>>> Transmission of stereo requires four times the transmitter power for the
>>> same S/N ratio as mono.
>>
>> The issue being debated was the amount of audible hiss when the FM tuner
>> is *set to stereo mode*, and its L and R outputs are subsequently
>> combined into mono, versus what happens when the FM tuner is *set to
>> mono mode* in the same situation.
>>
>> The answer of course, is that in both these scenarios, the amount of
>> audible hiss is exactly the same.
>
>
> That's obviously bullshit, because when you're listening to a slightly
> hissy stereo station and you switch to mono the hiss disappears. Therefore
> the amount of audible hiss has obviously been reduced.
**not when the tuners L and R outputs have been recombined into mono**
**fuckwit**
DAB sounds worse than FM
message
> On Tue, 18 Aug 2009 16:42:29 +0100, DAB sounds worse than FM wrote:
>
>>> Transmission of stereo requires four times the transmitter power
>>> for
>>> the same S/N ratio as mono.
>>>
>>> This provides another reason that the "powers that be" want to
>>> migrate
>>> to DAB - the FM transmitters are relatively high powered, and
>>> require a
>>> lot of expensive electricity.
>>
>>
>> Another idiotic comment from The Idiot. DAB receivers consume far
>> more
>> power than FM receivers, so multiply that by the number of
>> receivers
>> in-use at any given time and DAB consumes far more power than FM
>> overall.
>
> Right. I'll reply to this moron just once, then he can FOAD:
You do whatever you want. I'll carry on exposing your lack of
understanding of digital technologies on here for as long as you try
to have a go at me. Your knowledge of digital technologies is crap, so
it's like shooting fish in a barrel.
> The normal transmitter power of a DAB transmitter is (typically) two
> to
> three orders of magnitude less than a Band II regional transmitter.
Idiotic nonsense. Three orders of magnitude? You do put your
underpants on over your trousers, don't you? 3 orders of magnitude is
a factor of 1000. Main BBC DAB transmitter sites use ERPs of around
5 - 10 kW. Find me a BBC FM transmitter that has an ERP of 5 - 10 MW,
CLOWN. I'll even give you the links to make the search easier for you:
http://www.bbc.co.uk/reception/transmitters/radio/scotland_fm.shtml#Ashkirk
http://www.bbc.co.uk/reception/transmitters/radio/digital_radio.shtml
Oh, and good luck.
> You do understand what that means, don't you? No. I thought not.
Oh, the irony!!!!!
> In simple terms, so you can follow:
>
> It's going to take a hell of a lot of DAB transmitters and even more
> of
> these supposedly power-hungry receivers to come even close to the
> power
> budget of a /single/ Band II FM transmitter.
(a) there needs to be a a lot of DAB transmitters to provide the same
level of coverage as a big FM transmitter, because DAB signals don't
propagate as well as Band II signals
(b) DAB receivers consume far more power than FM receivers
(c) the UK public spends 1 billion hours per week listening to radio
Taking all of the above into consideration, DAB consumes more power
than FM overall.
> What a clueless fool.
Oh, the irony.
> On your stupid Arqiva jibe:
>
> http://www.radioscape.com/ might actually help you to understand
> what's
> going on, though it's unlikely you'd understand or choose to
> deliberately
> misunderstand what's written there. Who do you think Arqiva buy
> their
> coders from?
I have no need to visit the Radioscape website to know precisely what
that company does. It produces DAB (and DAB+/DMB/DRM) receiver modules
based on off-the-shelf DSP chips, and it produces DAB multiplexer
hardware. Its share of the DAB receiver module market has declined in
recent years due to its use of DSP chips meaning that its modules
couldn't compete with Frontier-Silicon's ASIC-based modules in terms
of power consumptions. This led to teh company going into
administration earlier this year, but it now seems to be back going
again.
Radioscape are not and never have been transmission network providers,
but that's what you seemed to think they did, because you were
confusing them with Arqiva, because hyou don't know what you're
talking about.
> Next:
>
> You obviously have no actual concept of received bandwidth - the
> reason
> for the relative noisiness of a stereo FM signal when compared to a
> mono
> one is purely determined by the received bandwidth.
Bullshit. The L+R signal is obviously going to have a higher power
than the L-R signal if there is a reasonably high correlation between
the L and the R signals, and it's rare that that isn't the case.
For example, if you have a digital value of 20,000 on the left channel
and 19,000 on the right channel, then:
L + R = 39,000
L - R = 1,000
(L+R) / (L-R) = 39 = 32 dB difference
Yet your explanation assumes that the signal power is equal on both
L+R and L-R. Wrong.
> The required
> bandwidth for Zenith-GE stereo is slightly more than four times that
> required for mono. Add in the other sub-carriers - the RDS, the
> stereo
> pilot and the control signals (which, like it or not, affect the
> noise
> content), and the overall noise floor on a good FM path is actually
> rather poor.
I'm not disputing that the bandwidth for stereo is approx 4 times that
of mono, so the noise power for stereo wiil be 4 times that when mono
is used. What I'm saying is that you're ignoring the difference in
signal power between the L+R and the L-R signals, so your suggestion
that there's only 6 dB (i.e. a factor of 4) difference in SNR was
incorrect.
> You're probably the kind of buffoon that still insists on listening
> to
> analogue tape and vinyl records,
I don't have any analogue sources in my hi-fi system other than my FM
tuner, actually, and that's been the case for almost a decade. I was
actually originally a fan of the concept of digital radio, but then
the BBC slashed the bit rates on DAB and the rest is history. I am
actually the opposite of a luddite, because I advocate the use of the
most advanced technologies available, and the luddites around here are
in fact those like yourself who're DAB apologists.
> and fondly believes that the compact
> cassette is an unsurpassed medium because "it can't get scratched".
> In
> that case, the noise inherent in stereo broadcasting will make you
> feel
> right at home. It's what you've come to expect. However, you're
> listening to a digital source (mostly CD or automated hard-disk
> based
> players) that are having their inherently excellent noise floor
> compromised by an ineffective FM broadcast path.
See above.
> "Halfwit" overestimates your intellect by a factor of at least two.
I've got 2 first class undergraduate degrees, so I doubt that somehow.
> You have NO IDEA what you're blathering on about,
I have an excellent understanding of digital communications theory
(that's what I specialised on my MSc in digital comms and DSP) and I
have a very good (i.e not excellent) understanding of compressed
audio. They're the two most relevant subjects to digital radio, so
you're wrong.
In comparison, up to now you've shown that you have a terrible
understanding of these subjects - although that hasn't stopped you
gobbing off about them.
> and invariably jump
> into every thread with your two club feet.
I only ever jump into a thread if I know what I'm talking about. You
do the opposite.
DAB sounds worse than FM
The FM signal described mathematically is as follows:
http://www.freepatentsonline.com/3728491.html
"M(t) = (L+R) + (L-R) cos ?t + P cos (?/2) t
Where M(t) is the composite signal
L is the left channel audio signal
R is the right channel audio signal
P is the pilot carrier amplitude
? = 2pf, f presently being 38 kHz"
One the L-R signal has been demodulated, the signals that are used to
reconstruct the stereo channels are:
L+R signal
L-R signal
But they have their own different noise signals on them.
The equations in my previous post were correct.
> This is also the type of mentality that prevents people like you
> from ever
> getting any degrees.
>
> Do you in all seriousness still deny that "n2" (as you call it) is
> 180degrees out of phase between the two stereo channels?
n1 and n2 are different signals altogether. n1 is the noise added to
the L+R signal, which is transmitted in a different part of the
spectrum to the L-R signal, so the n2 signal that's added to the L-R
signal is obviously different to n1.
n1 and n2 are Gaussian random noise signals, and there is 0% chance
that n1 == n2. 0% chance.
Are you disputing that the noise in the spectrum where n1 is
transmitted and the noise in the spectrum where n2 is transmitted:
http://upload.wikimedia.org/wikipedia/commons/c/cd/RDS_vs_DirectBand_FM-spectrum2.svg
is different? That would be ridiculous - it's the kind of thing I'd
expect an undergraduate Software Engineering student to come out with!
> <Sesame Street voice>
> You *add* the difference signal AND noise present on it, to recreate
> the
> left channel.
> You *subtract* the difference signal AND noise present on it, to
> recreate
> the right channel.
> </Sesame Street voice>
The additive noise signals on the L+R and L-R signals are different,
therefore when you add or subtract different random signals together
they do not cancel one another.
> The final + in your quack equation for the right channel above
> should
> actually be a minus.
Hooraaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyy!!!!!!!!!!!!
It makes no difference whether there's a plus or a minus sign - unless
the two noise signals are the same, and they're obviously not, one is
n1 and the other is n2.
The n1 and n2 noise signals are random processes (i.e. a time signal
of a random variable), and random processes have to be described by
their probability distributions / statistics. In this case, n1 and n2
are Gaussian random, zero-mean signals with the same variance
(variance = power). And if you add two such signals together the
resultant signal will have exactly the same statistics as if you
subtract the signals from one another. Therefore, it doesn't matter at
all whether I put a '+' or a '-' in front of n2 in the 2nd equation.
I suggest you brush up on your probability and random processes
theory.
> And since it's used so frivolously these days *clears throat*:
> QED.
You only get to say QED when you get something correct, Jimmy.
DAB sounds worse than FM
But we're talking about when you press the stereo/mono button on an FM
tuner and the hiss disappears.
jamie powell
You are just *****soo fucking thick***** and *****soo fucking deluded*****
it's beyond belief.
You can't even grasp the *one and only* *incredibly basic* point that I'm
making, which is that "n2" on the left channel output of an FM tuner is 180
degrees out of phase with "n2" on the right channel output - in other words
"n2" on each channel are *exact opposites* of one another, and therefore
"n2" cancels itself out when the two channels are combined into a mono
amplifier, giving the same result as if the tuner were set to mono mode.
Instead, all you can do is paste other people's technical specs and
technical descriptions randomly - including details which *aren't even
relevant* , in a desperate attempt to sound clueful.
You're about as much use as a talking parrot which has been left with
talkative broadcasting engineers for a few weeks.
jamie powell
We're talking about what happens when a stereo FM tuner is output through a
MONO radio's speaker which reproduces both L and R channels combined.
fuckwit.
DAB sounds worse than FM
No, YOU and only YOU are talking about that. People of sane mind are
talking about what happens when you hit the mono button on an FM
tuner.
Richard Evans
>
>
> The signals that are used to reconstruct the Left and Right stereo
> channels are as follows:
>
> L + R and L - R
>
> See:
> http://upload.wikimedia.org/wikipedia/commons/c/cd/RDS_vs_DirectBand_FM-spectrum2.svg
>
> But these signals have noise added by the RF front-end, so in reality
> the signals used to reconstruct the Left and Right channels are:
>
> L + R + n1
> L - R + n2
>
> where n1 and n2 are different noise signals (the bandwidth is
> different, so the noise is obviously different as well) added to the
> sum and difference signals respectively.
>
> The Left and Right stereo channels are reconstructed as follows:
>
> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>
> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2
>
> The noise on the Left and Right channels is therefore (n1 + n2)/2.
>
> In comparison, the noise added to the mono L + R signal is just n1
> (see above).
>
> n1 != (n1 + n2)/2
>
> QED.
>
>
>
All this is theory, but in the end I know that it works in practice.
My first stereo radio cassette player, didn't have a mono FM button. I
often used to play it through an old amp, which did have a mono button.
If I was listening to a weak stereo station and getting too much noise,
I would simply press the mono button on the amp, and it would
dramatically reduce the noise level, usually removing the noise all
together.
I also uploaded some samples last time we had this discussion, to
demonstrate the point. I recorded some noisy stereo audio, then used a
simple computer program to add the left and right channels together, to
turn it into mono. I uploaded both the stereo and mono versions and the
mono version had dramatically less noise.
Richard E.
DAB sounds worse than FM
news:4a8b25d4$1...@mk-nntp-2.news.uk.tiscali.com
> DAB sounds worse than FM wrote:
>
>>
>>
>> The signals that are used to reconstruct the Left and Right stereo
>> channels are as follows:
>>
>> L + R and L - R
>>
>> See:
>> http://upload.wikimedia.org/wikipedia/commons/c/cd/RDS_vs_DirectBand_FM-spectrum2.svg
>>
>> But these signals have noise added by the RF front-end, so in
>> reality
>> the signals used to reconstruct the Left and Right channels are:
>>
>> L + R + n1
>> L - R + n2
>>
>> where n1 and n2 are different noise signals (the bandwidth is
>> different, so the noise is obviously different as well) added to
>> the
>> sum and difference signals respectively.
>>
>> The Left and Right stereo channels are reconstructed as follows:
>>
>> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>>
>> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2
>>
>> The noise on the Left and Right channels is therefore (n1 + n2)/2.
>>
>> In comparison, the noise added to the mono L + R signal is just n1
>> (see above).
>>
>> n1 != (n1 + n2)/2
>>
>> QED.
>>
>>
>>
>
> All this is theory, but in the end I know that it works in practice.
It's both theory and practice.
> My first stereo radio cassette player, didn't have a mono FM button.
> I
> often used to play it through an old amp, which did have a mono
> button.
> If I was listening to a weak stereo station and getting too much
> noise,
> I would simply press the mono button on the amp, and it would
> dramatically reduce the noise level, usually removing the noise all
> together.
You're going on about the same thing Jim Powell was going on about
adding the L and the R channels together, but I was just going on
about normal mono buttons on an FM tuner.
Anyway, doesn't matter - at least I've exposed Jimmy Powell's
mathematical incompetence due to his inability to understand
Probability and Random Processes 101.
> I also uploaded some samples last time we had this discussion, to
> demonstrate the point. I recorded some noisy stereo audio, then used
> a
> simple computer program to add the left and right channels together,
> to
> turn it into mono. I uploaded both the stereo and mono versions and
> the
> mono version had dramatically less noise.
Yeah, I'm not disputing that adding the L and R outputs does cancel
the noise - IIRC from last time the equations do actually work out.
You said above "this is just theory", but so are most things, so if
the equations indicate something then it's still going to work out
like that when you implement it with electronics.
jamie powell
Have you fuck, you deluded POS.
>
>
>> I also uploaded some samples last time we had this discussion, to
>> demonstrate the point. I recorded some noisy stereo audio, then used a
>> simple computer program to add the left and right channels together, to
>> turn it into mono. I uploaded both the stereo and mono versions and the
>> mono version had dramatically less noise.
>
>
> Yeah, I'm not disputing that adding the L and R outputs does cancel the
> noise - IIRC from last time the equations do actually work out.
Pretending you knew it all along, as usual, yet at the same time standing by
your quack equations which contradict your new (correct) position.
Bill Wright
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>
You know that thing when you ask a simple question in the pub or at a party,
and people argue about the answer, and then a massive barney breaks out,
with bottles and chairs flying about? The joint gets wrecked and the owner
sends YOU the bill! "Well, you started it!"
That's me.
Bill
jamie powell
"Bill Wright" <insertmybu...@f2s.com> wrote in message
news:-4ednRKEpZu5phbX...@pipex.net...
I'm *totally* not the violent type. you should know me better by now :p
jamie
wrote:
> "jamie powell" <jamie_...@excite.com> wrote in message
>
> > We're talking about what happens when a stereo FM tuner is output
> > through
> > a MONO radio's speaker which reproduces both L and R channels
> > combined.
> > fuckwit.
>
> No, YOU and only YOU are talking about that. People of sane mind are
> talking about what happens when you hit the mono button on an FM
> tuner.
bollocks.
DAB sounds worse than FM
This is what you wrote:
"The final + in your quack equation for the right channel above should
actually be a minus."
That shows you failed to understand the maths involved. *Proper*
engineeering, as opposed to Software "Engineering", is all maths
(around 90 - 95% of engineering exam questions are maths questions),
but you misunderstood a really basic equation. You're a fake, Jamie.
You're actually worse than this Christopher Hunter fella, because at
least he worked as a proper engineer, albeit that he knows nothing
about digital technologies. You, on the other hand, have no relevant
knowledge or practical experience at all.
Go copy and paste some files like a good little Software "Engineer",
and leave the proper engineering to people who can understand the
maths, because you blatantly don't, and if you don't understand the
maths then you can't discuss the theory behind how things work.
>>> I also uploaded some samples last time we had this discussion, to
>>> demonstrate the point. I recorded some noisy stereo audio, then
>>> used a
>>> simple computer program to add the left and right channels
>>> together, to
>>> turn it into mono. I uploaded both the stereo and mono versions
>>> and the
>>> mono version had dramatically less noise.
>>
>>
>> Yeah, I'm not disputing that adding the L and R outputs does cancel
>> the
>> noise - IIRC from last time the equations do actually work out.
>
>
> Pretending you knew it all along, as usual, yet at the same time
> standing
> by your quack equations which contradict your new (correct)
> position.
Quack equation, eh? You mean the equation that you failed to
understand?
I think I'll call you Mr Maths Challenged from now on. Or Mr Maths
Incompetent. Or maybe just Idiot for short. Which would you prefer?
DAB sounds worse than FM
To be honest, me and Jimmy Powell don't need much of an excuse for an
argument...
jamie
wrote:
> "jamie powell" <jamie_...@excite.com> wrote in message
>
> news:h6faam$1k7$1...@aioe.org
>
>
>
> > "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> >news:7f0ntrF...@mid.individual.net...
> >>news:4a8b25d4$1...@mk-nntp-2.news.uk.tiscali.com
> >>> DAB sounds worse than FM wrote:
>
> >>>> The signals that are used to reconstruct the Left and Right
> >>>> stereo
> >>>> channels are as follows:
>
> >>>> L + R and L - R
>
> >>>> See:
Nope. The final + should be a minus. The + you wrote referred to "n2"
on the
right channel. You said "n2" was noise present on L-R. Since L-R is
subtracted from L+R to create the right channel, then "n2" is also
subtracted from L+R to create the right channel, hence a minus symbol
is in order.
simples!
> Go copy and paste some files like a good little Software "Engineer", and
> leave the proper engineering to people who can understand the maths,
> because you blatantly don't, and if you don't understand the maths then
> you can't discuss the theory behind how things work.
>
>
>>>> I also uploaded some samples last time we had this discussion, to
>>>> demonstrate the point. I recorded some noisy stereo audio, then used a
>>>> simple computer program to add the left and right channels together, to
>>>> turn it into mono. I uploaded both the stereo and mono versions and the
>>>> mono version had dramatically less noise.
>>>
>>>
>>> Yeah, I'm not disputing that adding the L and R outputs does cancel the
>>> noise - IIRC from last time the equations do actually work out.
>>
>>
>> Pretending you knew it all along, as usual, yet at the same time standing
>> by your quack equations which contradict your new (correct) position.
>
>
> Quack equation, eh? You mean the equation that you failed to understand?
>
> I think I'll call you Mr Maths Challenged from now on. Or Mr Maths
> Incompetent. Or maybe just Idiot for short. Which would you prefer?
aww look, little charlatan's been exposed again and he's getting
pissy.
If you knew some of the complex maths stuff I was involved with
steven, you
wouldn't even be able to comprehend it.
You see steven, you're just a wannabee, always have been, and always
will
be.
You crave a sense of glory and self-importance which you think comes
from
being a high-flying expert professional, but you have neither the
education
nor the intellect to even come close to becoming one, let alone the
emotional detachment.
So you choose to fake it (badly) on usenet instead. A few people
half-listen, but they come and they go, and they wouldn't care if you
got
run over by a bus tomorrow.
And that's your life innit.
Christopher Hunter
> The final + in your quack equation for the right channel above should
> actually be a minus.
The clueless "DAB Sounds Worse" cretin doesn't understand simple
mathematics. His "trading" should be very funny, if it exists. He's
wrongly copied the equations from an article he doesn't comprehend.
> And since it's used so frivolously these days *clears throat*: QED.
...and he obviously doesn't have the intellect for even an arts degree -
also QED!
DAB sounds worse than FM
message
> On Tue, 18 Aug 2009 18:57:54 +0100, jamie powell wrote:
>
>> The final + in your quack equation for the right channel above
>> should
>> actually be a minus.
>
> The clueless "DAB Sounds Worse" cretin doesn't understand simple
> mathematics.
That'll explain why I averaged 95% over my 3 maths exams at university
then.
> His "trading" should be very funny, if it exists.
Doesn't surprise me at all that you've said that, because you get
everything wrong.
> He's
> wrongly copied the equations from an article he doesn't comprehend.
Please point out where there's an error in those equations. There is
no error. And I don't need to copy simple equations.
DAB sounds worse than FM
news:32b2c9a0-7df7-45c1...@o15g2000yqm.googlegroups.com
Er, yes, I know that a - (+b) = a - b. This isn't pre-school algebra
we're doing, Jimmy.
But it still doesn't matter whether you put a plus or a minus in teh
2nd equation where I put a plus.
n1 and n2 are Gaussian random noise signals (AKA random processes).
You have to describe random signals (and random variables) by their
probability distributions, and a Gaussian (i.e. normal) distribution
is completely defined by its mean and variance. So I need to prove
that the mean and the variance of the probability distribution for n1
+ n2 are equal to the mean and variance of the probability
distribution for n1 - n2. Are you with me so far, Jimmy?
Call n3 the result of the adding/subtracting random variables n1 and
n2.
For n3 = n1 + n2:
The mean of n3 is:
E(n3) = E(n1 + n2) = E(n1) + E(n2)
but the mean (i.e. E(.)) of n1 and n2 is zero, so the mean of n3 = 0.
For n3 = n1 - n2, you've got the same equation as above, but the means
are still zero, so the mean of n3 is still zero. So the means of the
resulting distribution are the same whether you add or subtract. Okay?
The formula for the variance is Var(X) = E[(X - (E(X))^2].
For n3 = n1 + n2
Var(n3) = E[((n1 + n2) - E(n1 + n2))^2]
But the means of n3 is zero, so E(n1 + n2) = 0, so
Var(n3) = E[(n1 + n2)^2]
Multiplying out:
Var(n3) = E[n1^2 + 2 n1 n2 + n2^2]
Taking expectations:
Var(n3) = E(n1^2) + 2 E(n1 n2) + E(n2^2)
But E(n1 n2) = 0, because Gaussian random variables are independent,
so
Var(n1 + n2) = E(n1^2) + E(n2^2) [equation 1]
The variance for n3 = n1 - n2:
Var(n3) = E[((n1 - n2) - E(n1 - n2))^2]
Again, E(n1 - n2) = 0, so
Var(n3) = E[(n1 - n2)^2]
Multiplying out:
Var(n3) = E[n1^2 - 2 n1 n2 + n2^2]
Taking expectations:
Var(n3) = E(n1^2) - 2 E(n1 n2) + E(n2^2)
Again, E(n1 n2) = 0 due to independence, so
Var(n1 - n2) = E(n1^2) + E(n2^2) [equation 2]
Comparing equation 1 with equation 2:
Var(n1 + n2) = Var(n1 - n2)
QED.
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Hahahahhhahahahahahhahhahahhahahahahahahahahahahaahhahahahahahahahahahahaahaa
Jimmy doing complex maths! Hillarious!!
Engineer
> He's confused Radioscape (a DAB receiver module and DAB multiplex
> equipment manufacturer) with Arqiva (a transmission provider).
Not at all. It's YOU that doesn't know what's going on. Radioscape have
an effective monopoly on the manufacture and supply of DAB transmission
equipment. If you had the slightest idea about DAB broadcasting you'd
know that.
>> I'm seriously tempted to add another multiplex in my area, and offer /
>> very/ cheap carriage to any broadcaster that wants to use it....
That would be very funny, especially as the major reason for DAB
replacing FM is that it can be more easily government controlled. Anyone
can build an FM transmitter (unless you're "DAB Sounds Worse than FM"),
and the government will have a lot of trouble getting you off the air.
Look at the persistent problems caused by the pirate stations!
Bob
--
Everything gets easier with practice, except getting up in the morning.
DAB sounds worse than FM
news:7f3k6tF2...@mid.individual.net
> On Tue, 18 Aug 2009 17:26:23 +0100, DAB sounds worse than FM wrote:
>
>> He's confused Radioscape (a DAB receiver module and DAB multiplex
>> equipment manufacturer) with Arqiva (a transmission provider).
>
> Not at all.
Christopher, this has to be THE lamest attempt at someone trying to
pass themselves off as someone else I have ever seen in my life. And
shall I tell you why it's so bleeding obvious that this is you
attempting to pass yourself off as someone else? It's because you're
trying to back up what you originally said, but you happen to have got
it wrong again.
> It's YOU that doesn't know what's going on. Radioscape have
> an effective monopoly on the manufacture and supply of DAB
> transmission
> equipment.
WRONG. Radioscape don't make "DAB transmission equipment". They make
multiplexer hardware. And they don't have "an effective monopoly" on
that, because for example Factum Electronics in Sweden and VDL in
France and some others make DAB multiplexer hardware as well. And I
would suggest that Factum Electronics sell more multiplexer hardware
than Radioscape.
> If you had the slightest idea about DAB broadcasting you'd
> know that.
Oh, the irony.
>>> I'm seriously tempted to add another multiplex in my area, and
>>> offer /
>>> very/ cheap carriage to any broadcaster that wants to use it....
>
> That would be very funny, especially as the major reason for DAB
> replacing FM is that it can be more easily government controlled.
That is not the main reason why DAB is going to "replace" FM. It is
because the broadcasters see DAB as being the best way to protect
their existing audiences, whereas they fear that people who listen via
the Internet are less likely to listen to their stations, so their
answer is to force everyone onto DAB ASAP before Internt radio can
become established.
bolta...@yahoo.co.uk
Engineer <engi...@engineering.eng> wrote:
>That would be very funny, especially as the major reason for DAB
>replacing FM is that it can be more easily government controlled. Anyone
>can build an FM transmitter (unless you're "DAB Sounds Worse than FM"),
>and the government will have a lot of trouble getting you off the air.
>Look at the persistent problems caused by the pirate stations!
Unfortunately you'll have to blame an entire generation of paranoid fuckwit
baby boomers who were anti nuclear anything, for us not having a decent
nuclear power system and instead the government has to resort to mickey
mouse generation techniques to supposedly reduce our carbon footprint.
B2003
tony sayer
<engi...@engineering.eng> scribeth thus
>On Tue, 18 Aug 2009 17:26:23 +0100, DAB sounds worse than FM wrote:
>
>> He's confused Radioscape (a DAB receiver module and DAB multiplex
>> equipment manufacturer) with Arqiva (a transmission provider).
>
>Not at all. It's YOU that doesn't know what's going on. Radioscape have
>an effective monopoly on the manufacture and supply of DAB transmission
>equipment.
You sure about that?...
> If you had the slightest idea about DAB broadcasting you'd
>know that.
>
>>> I'm seriously tempted to add another multiplex in my area, and offer /
>>> very/ cheap carriage to any broadcaster that wants to use it....
>
>That would be very funny, especially as the major reason for DAB
>replacing FM is that it can be more easily government controlled. Anyone
>can build an FM transmitter (unless you're "DAB Sounds Worse than FM"),
>and the government will have a lot of trouble getting you off the air.
>Look at the persistent problems caused by the pirate stations!
>
>Bob
>
There is a design on the net for a home-brew DAB TX but I don't reckon
the pirates would use one not receivers around;!.
Apart from the number of Tx's required..
--
Tony Sayer
tony sayer
Bring on the windmills;!..
--
Tony Sayer
Richard Evans
And lets have a big barrier across the Severn Estuary.
Richard E.
Richard Evans
> There is a design on the net for a home-brew DAB TX but I don't reckon
> the pirates would use one not receivers around;!.
>
> Apart from the number of Tx's required..
>
If they ever manage to switch off FM, that might increase the number of
DAB receivers in use. It might then become worthwhile for the pirates to
start using DAB. Now wouldn't that be a little ironic.
Richard E.
Bill Wright
<bolta...@yahoo.co.uk> wrote in message news:h6j275$28r$1...@aioe.org...
In fact, my generation are not at the forefront of anti-nuclear feeling. I
know the grannies make the news whenever there's a demo, but that's just
media distortion for the sake of making the story 'interesting'. Most
anti-nuclear, anti-capitalist environmentalist puritans are from the younger
age groups.
Bill
Bill Wright
> tony sayer wrote:
> If they ever manage to switch off FM, that might increase the number of
> DAB receivers in use. It might then become worthwhile for the pirates to
> start using DAB. Now wouldn't that be a little ironic.
Well of course that would happen. However, FM won't be switched off. There
are no plans to switch FM off completely, just a plan to remove the national
networks. Even that incomplete plan is unlikely to succeed, because the
nationals would realise that they would lose vast numbers of listeners.
Bill
DAB sounds worse than FM
> "jamie" <jami...@excite.com> wrote in message
> news:32b2c9a0-7df7-45c1...@o15g2000yqm.googlegroups.com
>> Nope. The final + should be a minus. The + you wrote referred to
Jimmy seems to have conveniently gone AWOL.
Are you okay, Jimmy? Got swine flu all of a sudden or something?
Looking forward to your switft recovery, and your apology to myself,
and your admission of being mathematically challenged.
Regards.
bolta...@yahoo.co.uk
"Bill Wright" <insertmybu...@f2s.com> wrote:
>In fact, my generation are not at the forefront of anti-nuclear feeling. I
>know the grannies make the news whenever there's a demo, but that's just
>media distortion for the sake of making the story 'interesting'. Most
>anti-nuclear, anti-capitalist environmentalist puritans are from the younger
>age groups.
They are now because the hippy generation is too old to climb up trees
and build tunnels. But your generation started the rot and its going to
take another generation to get rid of it.
B2003
Bill Wright
<bolta...@yahoo.co.uk> wrote in message news:h6lo6d$b58$1...@aioe.org...
> On Thu, 20 Aug 2009 23:09:33 +0100
> "Bill Wright" <insertmybu...@f2s.com> wrote:
>>In fact, my generation are not at the forefront of anti-nuclear feeling. I
>>know the grannies make the news whenever there's a demo, but that's just
>>media distortion for the sake of making the story 'interesting'. Most
>>anti-nuclear, anti-capitalist environmentalist puritans are from the
>>younger
>>age groups.
>
> They are now because the hippy generation is too old to climb up trees
> and build tunnels.
We bloody are not. We can climb trees and build tunnels. I personally climb
many a tree, and my mate helped build the Channel Tunnel.
>But your generation started the rot and its going to
> take another generation to get rid of it.
It will take far longer than that. All this modern greeny bollocks is being
drummed into the little kids. All the teachers are Guardian-reading
anti-capitalist scum. You look at the wall displays in any junior school:
they're all about being kind to trees and throwing stones at passing
motorists. Meanwhile standards of proper education drop and the poor little
beggars can hardly read and write. It's lucky I abandoned teaching. There's
no way I could toe the PC line.
Bill
bolta...@yahoo.co.uk
"Bill Wright" <insertmybu...@f2s.com> wrote:
>It will take far longer than that. All this modern greeny bollocks is being
>drummed into the little kids. All the teachers are Guardian-reading
>anti-capitalist scum. You look at the wall displays in any junior school:
>they're all about being kind to trees and throwing stones at passing
>motorists. Meanwhile standards of proper education drop and the poor little
>beggars can hardly read and write. It's lucky I abandoned teaching. There's
Annoyingly I agree with you on everything there. I guess we'll have to have
an argument on another topic :)
B2003
jamie powell
>> on the
>> right channel. You said "n2" was noise present on L-R. Since L-R is
>> subtracted from L+R to create the right channel, then "n2" is also
>> subtracted from L+R to create the right channel, hence a minus symbol
>> is in order.
>> simples!
>
>
> Er, yes, I know that a - (+b) = a - b. This isn't pre-school algebra we're
> doing, Jimmy.
Still making up your own conventions to create complicated-looking quack
equations to represent highly simplistic theories then, Dabsworthless?
Trying to sneakily change your equations now to make people think you were
right the first time? (is anyone even bored enough to bother wading through
all your shite I wonder?)
> But it still doesn't matter whether you put a plus or a minus in teh 2nd
> equation where I put a plus.
I don't care about your equations, but you're still wrong in any event.
> n1 and n2 are Gaussian random noise signals (AKA random processes). You
> have to describe random signals (and random variables) by their
> probability distributions, and a Gaussian (i.e. normal) distribution is
> completely defined by its mean and variance. So I need to prove that the
> mean and the variance of the probability distribution for n1 + n2 are
> equal to the mean and variance of the probability distribution for n1 -
> n2. Are you with me so far, Jimmy?
You've picked up an ickle bit of basic terminology, but you don't know how
to use it.
It's like giving a set of expensive paintbrushes and canvasses to a monkey.
Firstly, what you call "n1" - the audible noise present on the mono L+R
signal - doesn't even come into this debate at all in any way, shape or
form. Never did, and never will.
We are talking spefically about what you call "n2" - the audible noise
present on the demodulated L-R subcarrier.
It makes no difference whether "n2" is random or not.
n1 - n2 *never* comes into the discussion. n2 - n2 *does*, though.
In other words, you're retarded, because this has been spelled out to you by
me and others many times. Are you with me so far, Dabsworthless?
> Call n3 the result of the adding/subtracting random variables n1 and n2.
>
> For n3 = n1 + n2:
>
> The mean of n3 is:
>
> E(n3) = E(n1 + n2) = E(n1) + E(n2)
>
> but the mean (i.e. E(.)) of n1 and n2 is zero, so the mean of n3 = 0.
>
> For n3 = n1 - n2, you've got the same equation as above, but the means are
> still zero, so the mean of n3 is still zero. So the means of the resulting
> distribution are the same whether you add or subtract. Okay?
Nobody said anything about n1 - n2 in this debate, retard.
See above, retard.
Writing out GCSE equations changes nothing, retard.
You haven't proved anything, retard.
*snips the rest because it's fundamentally flawed*
> QED.
Dabsworthless is retarded.
QED.
>> aww look, little charlatan's been exposed again and he's getting
>> pissy.
>>
>> If you knew some of the complex maths stuff I was involved with
>> steven, you
>> wouldn't even be able to comprehend it.
>
>
> Hahahahhhaha
*snip*
You laugh like Elmer Fudd, in the brief interval between setting a trap and
getting pwned by Bugs Bunny - the few moments when he thinks he's actually
'scored'
>
> Jimmy doing complex maths! Hillarious!!
The notion of Dabsworthless having any real clue! Doubly hilarous!!!
Let me finish with a meaningful equation which is actually *relevant* to the
subject being debated, using some of your own quack terminology to help you
understand it:
Stereo FM tuner set to FM mono mode:
Left = (L+R+n1)/2
Right = (L+R+n1)/2
Sum of Left and Right = L+R+n1
Stereo FM tuner set to FM stereo mode:
Left = ((L+R+n1) + (L-R+n2)) /2
Right = ((L+R+n1) - (L-R+n2)) /2
Sum of Left and Right = ( ((L+R+n1) + (L-R+n2)) /2 ) + ((L+R+n1) - (L-R+n2))
/2 ) = L+R+n1
QED, Steven. QED.
jamie powell
>
>
> Jimmy seems to have conveniently gone AWOL.
>
> Are you okay, Jimmy? Got swine flu all of a sudden or something?
>
> Looking forward to your switft recovery, and your apology to myself, and
> your admission of being mathematically challenged.
Your reply and subsequent personal embarassment awaits.
You're *really* sad if you think your haplessly-applied GCSE maths had
scared me off though.
Actually I've been busy helping a uni friend prepare for his resit exam, and
next week I'll be in Bangkok (a city in 'Thailand'. Thailand is a
'country'.) with another uni friend.
It's not a holiday as such though - I'm there to provide her with emotional
support and friendship, although I can't wait to visit the famous Siam
Paragon Mall :-)
Unfortunately Scott's away next week too, which leaves my cat's life is in
the hands of the strange lady who lives opposite us. She's always hugging me
and asking if I'm okay, and she seems abnormally worried in case any minor
bruises which I may or may not have were done by Scott. She's been like this
ever since I moved in 4 years ago, and still hasn't improved - strange lady.
(I'll stop blogging now - this is becoming like a Bill Wright "riggers
diary", and nearly as boring too).
Bill Wright
DAB sounds worse than FM
news:h6mm2q$kc3$1...@aioe.org
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7f62snF...@mid.individual.net...
>>
>>
>> Jimmy seems to have conveniently gone AWOL.
>>
>> Are you okay, Jimmy? Got swine flu all of a sudden or something?
>>
>> Looking forward to your switft recovery, and your apology to
>> myself, and
>> your admission of being mathematically challenged.
>
> Your reply and subsequent personal embarassment awaits.
I've given a mathematical proof that disproved something you claimed.
As such, it is literally impossible for me to be wrong, so I look
forward to seeing how you envisage I could possibly be embarrassed.
> You're *really* sad if you think your haplessly-applied GCSE maths
> had
> scared me off though.
There's no sadness or happiness about it. I've provided a proof, and
unless you can find something wrong with it then I'm right and you're
wrong. It's as simple as that.
> Actually I've been busy helping a uni friend prepare for his resit
> exam,
Hooraaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyy!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Jamie's failed one of his exams and he needs to
resit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Helping a friend, MY
ARSE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> and next week I'll be in Bangkok (a city in 'Thailand'. Thailand is
> a
> 'country'.) with another uni friend.
> It's not a holiday as such though - I'm there to provide her with
> emotional support and friendship, although I can't wait to visit the
> famous Siam Paragon Mall :-)
>
> Unfortunately Scott's away next week too, which leaves my cat's life
> is in
> the hands of the strange lady who lives opposite us. She's always
> hugging
> me and asking if I'm okay, and she seems abnormally worried in case
> any
> minor bruises which I may or may not have were done by Scott. She's
> been
> like this ever since I moved in 4 years ago, and still hasn't
> improved -
> strange lady.
Jamie, no-one likes you on here because you're an obnoxious little
twat to everybody you come across, so I'm not entirely sure why you
think anybody would be interested in what you have to say about your
personal life.
> (I'll stop blogging now - this is becoming like a Bill Wright
> "riggers
> diary", and nearly as boring too).
Bill's "rigger's diary" blog posts == usually very funny.
Jamie's story about is life == wrist-slittingly boring
Bill Wright
"jamie powell" <jami...@excite.com> wrote in message
news:h6mm2q$kc3$1...@aioe.org...
>
> Unfortunately Scott's away next week too, which leaves my cat's life is in
> the hands of the strange lady who lives opposite us. She's always hugging
> me and asking if I'm okay, and she seems abnormally worried in case any
> minor bruises which I may or may not have were done by Scott. She's been
> like this ever since I moved in 4 years ago, and still hasn't improved -
> strange lady.
you.
>
> (I'll stop blogging now - this is becoming like a Bill Wright "riggers
> diary", and nearly as boring too).
Rubbish! You will never be as boring as me! I am the king!
A few weeks ago a person I know who can be extremely amusing but can also be
a dreadful bore invited us out for a pint. Basically he just wanted an
audience, as we were to discover. No sooner had we sat down than he launched
into a monologue on a subject with which we were already all too familiar.
This was the long history of his local political infighting. It wouldn't
have been so bad if he'd just updated us, but he started at what had been
happening a year ago and gave us a blow by blow account of every minute
thing that had happened since then. Of course we were already familiar with
all this, except for the events of the last week or so. After 44 solid
minutes (yes, forty-four flipping minutes) he noticed that i was slumped in
my seat and was stating glassily at the ceiling. "Am I boring you?" he
enquired. And do you know, like a bloody coward I said, "No, not at all.
Please carry on." Doh!
There! You see! That was much more boring than what you said!
Bill
jamie powell
How rude (and unjustifiable) to call me a "deplorable person".
jamie powell
> I've given a mathematical proof that disproved something you claimed. As
> such, it is literally impossible for me to be wrong, so I look forward to
> seeing how you envisage I could possibly be embarrassed.
You're so self-deluded, you'll just delude yourself into thinking that's the
case and then treat yourself to the usual big dose of self-important
emotional smugness that seems to sugarcoat your entire hollow life.
>
>Hooraaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyy!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>
> Jamie's failed one of his exams and he needs to
> resit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
You wish. I find most of them really easy to be honest, and haven't ever
failed one.
> Jamie, no-one likes you on here because you're an obnoxious little twat to
> everybody you come across, so I'm not entirely sure why you think anybody
> would be interested in what you have to say about your personal life.
Welcome to usenet. Unlike you though, I have friends in the real world who
really do care about me.
Also unlike you, I actually do contribute to society, through my compassion
for others, and through my academic (soon to be professional) career.
By contrast, all you do is arbitrarily shove your head up your own arse,
waste oxygen, and waste internet bandwidth.
> Bill's "rigger's diary" blog posts == usually very funny.
Simple minds....Simple things....
> Jamie's story about is life == wrist-slittingly boring
What a shame you didn't.
DAB sounds worse than FM
news:h6mm2k$kbh$1...@aioe.org
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7f2r40F...@mid.individual.net...
<snip Jamie Gobshite's attempt at changing the subject completely
because he knows he's wrong>
Gobshite, let me remind you what the subject is, because you've just
gone to great lengths to try and change teh subject as far away from
the original subject as possible.
You wrote this:
"Nope. The final + should be a minus. The + you wrote referred to "n2"
on the
right channel. You said "n2" was noise present on L-R. Since L-R is
subtracted from L+R to create the right channel, then "n2" is also
subtracted from L+R to create the right channel, hence a minus symbol
is in order.
simples!"
You were referring to the following equations:
"The Left and Right stereo channels are reconstructed as follows:
Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
You had an issue with the plus sign in the last equation because the
noise terms in the square brackets for the last equation would
ordinarily have worked out to be (n1 - n2)/2, and you didn't
understand why writing (n1 + n2)/2 is equally correct, so you claimed
that how I wrote it was incorrect.
It should really be obvious when you just think about it for a few
seconds that if you add two zero-mean normally distributed random
variables together it wouldn't make any difference if you subtracted
the two random variables - they're RANDOM numbers, DUH! But clearly
the logic of the situation was beyond your maths-challenged brain, and
despite the fact that I tried to explain the situation to you, you
still tried to dispute that you were wrong. But anyway, I provided a
mathematical proof that shows that it doesn't matter whether you write
(n1 + n2)/2 or (n1 - n2)/2, because the resultant noise signal will
have identical signal statistics whether you use a + or a -. A copy of
the proof is as follows:
"Call n3 the result of the adding/subtracting random variables n1 and
n2.
For n3 = n1 + n2:
The mean of n3 is:
E(n3) = E(n1 + n2) = E(n1) + E(n2)
but the mean (i.e. E(.)) of n1 and n2 is zero, so the mean of n3 = 0.
For n3 = n1 - n2, you've got the same equation as above, but the means
are still zero, so the mean of n3 is still zero. So the means of the
resulting distribution are the same whether you add or subtract. Okay?
The formula for the variance is Var(X) = E[(X - (E(X))^2].
For n3 = n1 + n2
Var(n3) = E[((n1 + n2) - E(n1 + n2))^2]
But the means of n3 is zero, so E(n1 + n2) = 0, so
Var(n3) = E[(n1 + n2)^2]
Multiplying out:
Var(n3) = E[n1^2 + 2 n1 n2 + n2^2]
Taking expectations:
Var(n3) = E(n1^2) + 2 E(n1 n2) + E(n2^2)
But E(n1 n2) = 0, because Gaussian random variables are independent,
so
Var(n1 + n2) = E(n1^2) + E(n2^2) [equation 1]
The variance for n3 = n1 - n2:
Var(n3) = E[((n1 - n2) - E(n1 - n2))^2]
Again, E(n1 - n2) = 0, so
Var(n3) = E[(n1 - n2)^2]
Multiplying out:
Var(n3) = E[n1^2 - 2 n1 n2 + n2^2]
Taking expectations:
Var(n3) = E(n1^2) - 2 E(n1 n2) + E(n2^2)
Again, E(n1 n2) = 0 due to independence, so
Var(n1 - n2) = E(n1^2) + E(n2^2) [equation 2]
Comparing equation 1 with equation 2:
Var(n1 + n2) = Var(n1 - n2)
QED."
Now, Jamie Gobshite, what you have to do is find an inaccuracy in the
above proof, or else admit that your original statement about me
writing (n1 + n2)/2 was incorrect.
It's as simple as that.
You cannot change the subject, and any attempts at doing so will
simply be snipped by me.
It's put up or STFU time, Gobshite.
Oh, and good luck with resitting your exam next week, BTW.
jamie powell
Clearly I didn't go "back to basics" enough in my last post, and space has
been left for your idiocy and self-delusions to creep back in.
Let me make this *absolutely clear* - the *one* thing we disagreed on was
whether or not what you call "n2" - as heard when an FM stereo tuner is
receiving a weak signal in its "stereo mode" - is cancelled out when said
tuner's L and R outputs are combined. I couldn't care less about what you
call "n1" for the sake of this argument - I don't even care whether any "n1"
noise exists or not.
My (correct) position = "n2" is completely cancelled out when said tuner's L
and R outputs are combined into mono, and the user hears exactly what s/he
would hear if the tuner was set to mono mode in this same situation, because
n2 - n2 = 0. n2 is 180 degrees out of phase between the two channels, and
therefore n2 cancels itself out.
The Dabsworthless position = "It doesn't cancel out, and I criticized a
radio in one of my crappy reviews which no-one even reads as a result." then
"OK it does cancel out" then "Jamie's wrong - here's a few long-winded quack
equations to prove it!"
I stand by my assertion that the last + in the equation I originally
corrected should indeed be a minus. It's important to acknowledge this fact
because, although n2 is a "random variable", it's an exact opposite of the
same "random variable" in the left channel.
Soo, in the context of the issue of debate here, it's just as important that
we acknowledge that "n2" is being *subtracted* from the right channel as it
is that we acknowledge that "L-R" is being *subtracted* from the right
channel.
A copy of the proof is as follows:
Firstly, what you call "n1" - the audible noise present on the mono L+R
signal - doesn't even come into this debate at all in any way, shape or
form. Never did, and never will.
We are talking spefically about what you call "n2" - the audible noise
present on the demodulated L-R subcarrier.
It makes no difference whether "n2" is random or not.
n1 - n2 *never* comes into the discussion. n2 - n2 *does*, though.
In other words, you're retarded, because this has been spelled out to you by
me and others many times. Are you with me so far, Dabsworthless?
Nobody said anything about n1 - n2 in this debate, retard.
Writing out GCSE equations changes nothing, retard.
You haven't proved anything, retard.
The following meaningful equation is actually *relevant* to the
subject being debated. It uses some of your own quack terminology to help
you
understand it:
Stereo FM tuner set to FM mono mode:
Left = (L+R+n1)/2
Right = (L+R+n1)/2
Sum of Left and Right = L+R+n1
Stereo FM tuner set to FM stereo mode:
Left = ((L+R+n1) + (L-R+n2)) /2
Right = ((L+R+n1) - (L-R+n2)) /2
Sum of Left and Right = ( ((L+R+n1) + (L-R+n2)) /2 ) + ((L+R+n1) - (L-R+n2))
/2 ) = L+R+n1
> Oh, and good luck with resitting your exam next week, BTW.
I think it's v. amusing how you've siezed on the fact that I'm helping a
friend from my own degree course prepare for an exam which I myself passed
and he failed, and tried to twist it around without evidence to imply that I
myself am the failer.
You might as well say "Jamie's actually the one having sex reassignment
surgery in Thailand next week and not his uni friend whom he claims to be
going there with."
Neither of these assertions, even if true, would be cause for ridicule in
any event, but, of course, steven the 40 year old child just grabs any lame
excuse to feel superior by poking fun.
DAB sounds worse than FM
<snipped due to irrelevance>
> Stereo FM tuner set to FM mono mode:
> Left = (L+R+n1)/2
> Right = (L+R+n1)/2
> Sum of Left and Right = L+R+n1
>
> Stereo FM tuner set to FM stereo mode:
> Left = ((L+R+n1) + (L-R+n2)) /2
> Right = ((L+R+n1) - (L-R+n2)) /2
> Sum of Left and Right = ( ((L+R+n1) + (L-R+n2)) /2 ) + ((L+R+n1) -
> (L-R+n2)) /2 ) = L+R+n1
We are ***********NOT********** discussing the reconstruction of an FM
mono signal from the FM stereo channels, therefore the above equations
are totally irrelevant.
The discussion started when I quoted the equations used to reconstruct
the FM STEREO channels:
http://groups.google.com/group/alt.radio.digital/msg/3d10540af7b4b9e3?hl=en
> "The Left and Right stereo channels are reconstructed as follows:
>
> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>
> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
Here's your reply to the above post:
http://groups.google.com/group/alt.radio.digital/msg/fce84f87d65852d0?hl=en
In your reply, you said this:
"The final + in your quack equation for the right channel above should
actually be a minus. "
I have PROVED that it makes no difference whether you use a '+' or a
'-' in the equation for the Right channel. What you need to do is
either show that I've made an error in my proof, or I've won the
argument.
I will continue to snip any attempts you make to change the subject.
Put up or STFU, Jamie Gobshite.
DAB sounds worse than FM
> Put up or STFU, Jamie Gobshite.
Whoops, forgot to use your full name: Jamie "maths dunce" Gobshite.
Sorry about that - won't happen again.
jamie powell
>
>
> We are ***********NOT********** discussing the reconstruction of an FM
> mono signal from the FM stereo channels, therefore the above equations are
> totally irrelevant.
We are discussing difference between a mono signal created by summing the L
and R channels from the output of an FM stereo tuner -vs- the plain old mono
signal from an FM mono tuner (or an FM stereo tuner set to mono mode). You
are *very well aware* of this and have been all along. You got it wrong last
year and made a fool of yourself, and now you've got it wrong again.
> The discussion started when I quoted the equations used to reconstruct the
> FM STEREO channels:
>
> http://groups.google.com/group/alt.radio.digital/msg/3d10540af7b4b9e3?hl=en
>
>> "The Left and Right stereo channels are reconstructed as follows:
>>
>> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>>
>> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
>
>
> Here's your reply to the above post:
>
> http://groups.google.com/group/alt.radio.digital/msg/fce84f87d65852d0?hl=en
>
> In your reply, you said this:
>
> "The final + in your quack equation for the right channel above should
> actually be a minus. "
>
> I have PROVED that it makes no difference whether you use a '+' or a '-'
> in the equation for the Right channel. What you need to do is either show
> that I've made an error in my proof, or I've won the argument.
I stand by my assertion that the last + in the equation should indeed be a
minus.
It's important to acknowledge this fact because, although n2 is a "random
variable", it's an exact opposite of the same "random variable" in the left
channel.
Soo, in the context of the issue of debate here, it's just as important that
we acknowledge that "n2" is being *subtracted* from the right channel as it
is that we acknowledge that "L-R" is being *subtracted* from the right
channel.
You have *not* proved anything to the contrary.
> I will continue to snip any attempts you make to change the subject.
I shall continue to dismiss any further attempts you make to mislead your
non-existent audience as to the issue being debated and/or your lack of clue
on these matters.
> Put up or STFU, Jamie Gobshite.
Insults don't win you respect. Nor do they make you right.
Bill Wright
>
> You wish. I find most of them really easy to be honest, and haven't ever
> failed one.
Nor me. I normally failed all of them.
Bill
jamie powell
Even your 'O' level English? Your spelling and punctuation do seem
reasonable, unless your spelling and grammar checker software is "running
the show" on your behalf.
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
> news:7f8jdgF...@mid.individual.net...
>>
>>
>> We are ***********NOT********** discussing the reconstruction of an
>> FM
>> mono signal from the FM stereo channels, therefore the above
>> equations
>> are totally irrelevant.
>
What was being discussed is actually irrelevant.
The one and only issue is whether you can substitute a plus in place
of a minus when combining random signals.
The discussion started here:
http://groups.google.com/group/alt.radio.digital/msg/3d10540af7b4b9e3?hl=en
> "The Left and Right stereo channels are reconstructed as follows:
>
> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>
> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
Here's your reply to the above post:
http://groups.google.com/group/alt.radio.digital/msg/fce84f87d65852d0?hl=en
In your reply, you said this:
"The final + in your quack equation for the right channel above should
actually be a minus. "
I have PROVED that it makes no difference whether you use a '+' or a
'-' in the equation for the Right channel. What you need to do is
either show that I've made an error in my proof, or I've won the
argument.
I will continue to snip any attempts you make to change the subject.
Put up or STFU, Jamie Gobshite.
--
Bill Wright
> How rude (and unjustifiable) to call me a "deplorable person".
Well, I don't know Jamie. You've set out to appear obnoxious on this
newsgroup, you can't deny that, and even though I know you are really a nice
bloke, I thought I'd play along with your assumed persona.
Bill
Bill Wright
Look guys. Shall I just tell my nephew to buy a new radio? Then we can all
go to bed.
Bill
jamie powell
steven irks me with his quackery, that's all.
Isn't a "bloke" typically older than 20 btw? I'd sooner just be labelled "a
nice guy" :p
jamie powell
> "jamie powell" <jami...@excite.com> wrote in message
> news:h6n86o$v5$1...@aioe.org
>> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
>> news:7f8jdgF...@mid.individual.net...
>>>
>>>
>>> We are ***********NOT********** discussing the reconstruction of an FM
>>> mono signal from the FM stereo channels, therefore the above equations
>>> are totally irrelevant.
>>
>> We are discussing <snip>
>
>
> What was being discussed is actually irrelevant.
bollocks.
> The one and only issue is whether you can substitute a plus in place of a
> minus when combining random signals.
You can't if it's the *exact same* random signal being *subtracted* from the
right channel as is being *added* to the left!
> The discussion started here:
>
> http://groups.google.com/group/alt.radio.digital/msg/3d10540af7b4b9e3?hl=en
>
>> "The Left and Right stereo channels are reconstructed as follows:
>>
>> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>>
>> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
>
>
> Here's your reply to the above post:
>
> http://groups.google.com/group/alt.radio.digital/msg/fce84f87d65852d0?hl=en
>
> In your reply, you said this:
>
> "The final + in your quack equation for the right channel above should
> actually be a minus. "
>
> I have PROVED that it makes no difference whether you use a '+' or a
> '-' in the equation for the Right channel. What you need to do is
> either show that I've made an error in my proof, or I've won the
> argument.
If you're asking for me to respond with pointless quack equations like
yours, then you got the wrong guy mister!
I stand by my assertion that the last + in your "equation" should indeed be
jamie powell
> Look guys. Shall I just tell my nephew to buy a new radio? Then we can all
> go to bed.
Ironically, this debate isn't about your nephew's (presumably-broken)
radio - it's about stereo-capable radios which actually do correctly sum the
L and R stereo channels together before feeding them to the internal mono
speaker.
DAB sounds worse than FM
I'll start a new thread about this, as you're clearly only interested
in changing the subject because you refuse to admit that you're wrong.
jamie powell
>
>
> I'll start a new thread about this, as you're clearly only interested in
> changing the subject because you refuse to admit that you're wrong.
You plan to mislead your "audience" with more quackery in a new thread, and
slag me off at the same time, whilst freeing yourself of the damning
scientific facts I've provided in this one?
Do have fun with that...
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
<snip>
I was going to start a new thread, but I can't be arsed, because I'm
just wasting my time trying to get you to admit that you're wrong,
because you'd do anything rather than admit it.
I'm not actually sure whether you do understand why you're wrong, but
I'm sure you do realise that you're wrong, and you're deliberately
changing the subject to "what we were discussing" (even though that
was irrelevant) in a desperate attempt to stop discussing the bit that
you either don't understand, or if you do understand it you know you
can't win the argument because it's impossible to argue against a
mathematical proof.
Ultimately, your poor maths skills have been exposed. Disputing what I
said the first time wasn't the best, but you even disputed what I was
saying after I had explained the maths to you, and this is an easy
maths concept to understand, so I hereby announce that, Jamie:
You Are Crap At Maths.
Unlucky.
DAB sounds worse than FM
> "jamie powell" <jami...@excite.com> wrote in message
> news:h6mo4a$pds$1...@aioe.org...
>> How rude (and unjustifiable) to call me a "deplorable person".
>
> Well, I don't know Jamie. You've set out to appear obnoxious on this
> newsgroup, you can't deny that, and even though I know you are
> really a
> nice bloke,
Where do you get that he's "really a nice bloke"? I don't get any such
vibes from him.
jamie powell
> "jamie powell" <jami...@excite.com> wrote in message
> news:h6navm$56f$1...@aioe.org
>> "DAB sounds worse than FM" <dab...@fooked.com> wrote in message
>
> <snip>
>
>
> I was going to start a new thread, but I can't be arsed, because I'm just
> wasting my time trying to get you to admit that you're wrong, because
> you'd do anything rather than admit it.
>
> I'm not actually sure whether you do understand why you're wrong, but I'm
> sure you do realise that you're wrong, and you're deliberately changing
> the subject to "what we were discussing" (even though that was irrelevant)
> in a desperate attempt to stop discussing the bit that you either don't
> understand, or if you do understand it you know you can't win the argument
> because it's impossible to argue against a mathematical proof.
>
> Ultimately, your poor maths skills have been exposed. Disputing what I
> said the first time wasn't the best, but you even disputed what I was
> saying after I had explained the maths to you, and this is an easy maths
> concept to understand, so I hereby announce that, Jamie:
>
> You Are Crap At Maths.
>
> Unlucky.
Best wait until I'm in Thailand to start your new thread - that way I'm less
likely to respond in a timely fashion, and you can enjoy that hollow
smugness for a while longer before I come back and pwn you again. :p
DAB sounds worse than FM
Jamie, I'm not doing this to feel smug - you're a 2nd year undergrad
Software Engineering student.
I'm doing it because you need to be taught a lesson, because you gob
off all the fucking time, but you don't seem to realise how frequently
you're wrong, and you certainly never admit that you're wrong even
when you do realise you're wrong - and I'm sure you realise you're
wrong in this sub-thread, whether you actually understand why you're
wrong or not.
jamie powell
Do you, in all seriousness, still deny that "n2" (the noise present on
demodulated L-R as heard by the listener) cancels itself out when the L and
R outputs of an FM stereo tuner are summed into mono?
Bill Wright
No. I have a favourite little bloke and he's only just crawling.
Bill
Bill Wright
>
> You plan to mislead your "audience"
Sorry guys, they've all tiptoed out. I'm only here because someone has to
lock up.
Bill
Bill Wright
OK I'll tell him that.
Bill
DAB sounds worse than FM
What happens with n2 when the Left and Right channel signals are
summed together is irrelevant to the current discussion. The only
thing being discussed here is a point about maths:
http://groups.google.com/group/alt.radio.digital/msg/3d10540af7b4b9e3?hl=en
> "The Left and Right stereo channels are reconstructed as follows:
>
> Left = 0.5 * [(L + R + n1) + (L - R + n2)] = L + (n1 + n2)/2
>
> Right =0.5 * [(L + R + n1) - (L - R + n2)] = R + (n1 + n2)/2"
And in your reply to that post you claimed I'd made a mistake
http://groups.google.com/group/alt.radio.digital/msg/fce84f87d65852d0?hl=en
"The final + in your quack equation for the right channel above should
actually be a minus. "
So it doesn't matter which FM configuration we were talking about,
because the only thing being discussed *now* is whether my use of the
+ sign was correct or not.
I've given a mathematical proof that shows that it doesn't matter
whether you use a plus or a minus in front of n2 in the above
equation, so you need to either show that my
proof is wrong or admit that you were wrong to dispute my use of the
plus sign.
To have another go at explaining to you, in English rather than using
maths, why
it doesn't matter whether you use a plus or a minus sign, it's easier
to think about it in the digital domain, because the signals are just
numbers, rather than continuous waveforms. The n1 and n2 digital
signals would be simulated by drawing numbers from a random number
generator that produces normally distributed random numbers. Normally
distributed random numbers are independent from one another - i.e. the
random number generated doesn't depend on any of the previous random
numbers that were generated (coin tosses are independent, for example,
because if the previuos coin toss was a heads that doesn't have any
effect on the outcome of the next coin toss).
So the values of n2 are independent random numbers, and they also have
a zero mean, i.e. there's a 50% chance that the value that the random
number generator produces is positive and a 50% chance that the number
is negative.
Can you not see that inverting (i.e. making positive numbers negative
and making negative numbers positive) the n2 signal wouldn't make any
difference, because the numbers that make up the n2 signal are purely
random anyway.