opposite of an RF Modulator?
mm
take RF and turn it into digital for a digital tv?
Details:
I don't need this yet but I'm trying to plan ahead. What will I do
when I have one or two digital tvs, but I'm sending analog to all the
tvs in the house? I don't have the energy anymore to install
homeruns from the DVDR to any tv but the one in the same room. All
the rest are in series ther. I don't have the energy to run RCA
cables for composite or component inputs.
Right now, I use a DVDR and an RF modulator to take digital over the
air tv, detect it, and convert it to analog. and I send it to the 7
tv's I have, one in each room, and maybe one for the deck too. After
some effort, with some help from you guys, this works fine. The attic
antenna goes to the DVDR in my bedroom and soon, I'll have a set-top
box too (and a Channelplus modulator outputing two inputs on separate
channels), so I can record one show and watch a second, while sending
the second throughout the house.
I'm not going to buy 8 digital tv's at one time, and in reality, I'm
only going to get them one at a time over the next 10 or 20 years,
dpending on what I see at yard sales.
So what will I do when I have one or two digital tvs, but I'm sending
analog to all the tvs? I don't have the energy anymore to install
homeruns from the DVDR to any tv but the one in the same room. All
the rest are in series. I don't have the energy to run RCA cables for
composite or component.
Can I convert the analog back to digital for the digital tvs?
Bob AZ
MM
The opposite of a RF Modulator is a RF Demodulator. These take many
forms depending on what you would like to recover from a modulated
signal. A RF receiver is a form of a demodulator. It recovers the
signal from the modulated RF signal and outputs it as whatever. Think
AM and FM. These further come in types such as analog, digital, pulse
and others. What detects this information is many faceted. The one
that comes to mind is a simply diode detector that designed to a
plethora of specifications is wide or narrow band, freauency sensitive
and anything else you would like. I am sure Wikipedia has lots of
discussion that would prove interesting to you.
Bob AZ
Rich Webb
[snippety snip]
>So what will I do when I have one or two digital tvs, but I'm sending
>analog to all the tvs?
Some (many? most? all?) current generation U.S. flat-screen television
receivers include both NTST (analog) and ATSC (digital) tuners. The NTSC
tuners work the same way on the flat-screens as they do for the older,
CRC-based models, so you may not need to make any changes to your
distribution system at all.
>Can I convert the analog back to digital for the digital tvs?
Not easily or cheaply. The consumer-grade market for such a gizmo is
very small. If you wanted to do the heavy lifting, the specs for each
are available and it certainly could be done in principle. Some guy with
a web page has probably already done it but you're not likely to find
one on the shelf at WalMart.
--
Rich Webb Norfolk, VA
AZ Nomad
>take RF and turn it into digital for a digital tv?
it's called a tuner
William Sommerwerck
To make a long story short... Almost all TVs have inputs for analog audio
and video. By that I mean "baseband" (not RF) signals, such as composite
NTSC or component 1080p. With high-quality cabling, you should be able to
run these signals to multiple sets.
David Brodbeck
> it's called a tuner
I used to use a VCR as a tuner in my TV projection setup. Worked
pretty well. I bet an old VCR with a busted tape transport can be had
pretty cheaply these days.
Jim Yanik
news:ht3f3e$jpu$1...@news.eternal-september.org:
I don't know if those outputs are made to drive -multiple- sets.
I believe they are only 1:1.
They still require impedance matching,too.
--
Jim Yanik
jyanik
at
localnet
dot com
UCLAN
> Does there exist the opposite of an RF Modulator? Something that will
> take RF and turn it into digital for a digital tv?
Well, a RF *demodulator* takes analog RF and converts it to analog A/V. A
A->D converter will convert that to digital.
> Can I convert the analog back to digital for the digital tvs?
A A->D converter will do the trick. $$ for video.
Question: For the digital TVs, why not just use the original digital
signal?
David Nebenzahl
Just curious: what *is* the impedance of such cables? I'm guessing it's
not the 50 or 75 ohms of RF cabling.
--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.
- Comment from an article on Antiwar.com (http://antiwar.com)
Michael A. Terrell
David Nebenzahl wrote:
>
> On 5/20/2010 11:36 AM Jim Yanik spake thus:
>
> > "William Sommerwerck" <grizzle...@comcast.net> wrote in
> > news:ht3f3e$jpu$1...@news.eternal-september.org:
> >
> >> I think this is a troll, but...
> >>
> >> To make a long story short... Almost all TVs have inputs for analog audio
> >> and video. By that I mean "baseband" (not RF) signals, such as composite
> >> NTSC or component 1080p. With high-quality cabling, you should be able to
> >> run these signals to multiple sets.
> >
> > I don't know if those outputs are made to drive -multiple- sets.
> > I believe they are only 1:1.
> >
> > They still require impedance matching,too.
>
> Just curious: what *is* the impedance of such cables? I'm guessing it's
> not the 50 or 75 ohms of RF cabling.
They have to be made to drive a 75 ohm load to work with a standard
video input. If you can turn off the 75 ohm termination in all but the
last monitor, you can drive multiple monitors. I used the tuner & power
supply from a damaged VCR 20+ years ago as a secondary demodulator at
the TV station I worked at. I looped it back into a spare input on the
3M video router so the director could see what our views saw, instead of
our in hose video. That cost be $2, instead of over $3,000 for a
commercial demodulator like the one we used at our transmitter site.
--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.
mm
I don't know. I guess I can. I didnt' think of it. Thanks.
I guess I would have to use a couple spitters to make a route around
the RF modulator, and then I would be running analog and digital on
the same co-ax, right?
mm
<bbe...@mapson.nozirev.ten> wrote:
>On Thu, 20 May 2010 01:19:04 -0400, mm <NOPSAM...@bigfoot.com> wrote:
>
>[snippety snip]
>>So what will I do when I have one or two digital tvs, but I'm sending
>>analog to all the tvs?
>
>Some (many? most? all?) current generation U.S. flat-screen television
>receivers include both NTST (analog) and ATSC (digital) tuners. The NTSC
>tuners work the same way on the flat-screens as they do for the older,
>CRC-based models, so you may not need to make any changes to your
>distribution system at all.
Well that would be great. I'll keep my eyes open for that.
>>Can I convert the analog back to digital for the digital tvs?
>
>Not easily or cheaply. The consumer-grade market for such a gizmo is
>very small. If you wanted to do the heavy lifting, the specs for each
>are available and it certainly could be done in principle. Some guy with
>a web page has probably already done it but you're not likely to find
>one on the shelf at WalMart.
Okay.
Thanks to you and to Bob, AZ, David, William (even though he thinks
I'm trolling!) Jim, David, Michael, and UCLAN.
William Sommerwerck
> he thinks I'm trolling!) Jim, David, Michael, and UCLAN.
There are some questions that -- to me, anyway -- have such obvious and
simple answers, that it's easy to believe some posts are trolls.
Jeroni Paul
> Can I convert the analog back to digital for the digital tvs?
Not easy, a quality real time MPEG coder takes a lot of computing
power and the mass market does not request such device, so for now it
is expensive. However I'm guessing you are thinking for the future
when TVs are no longer equipped with analog tuners. At least a
baseband video input is likely to be available in TVs for a long time
so an easy option would be an external analog tuner. Yes, they exist
and even have remote control just like digital tuners.
However chances are that MPEG coders and CODFM modulators become cheap
enough for domestic use in the future or even DVDs, etc output a
modulated digital RF signal just like old VCRs did with an analog RF
channel. Yet I belive it is (and will be) cheaper to buy a DVD or
other set top box for every TV than to distribute the signal from one.
UCLAN
If you split it off to the digital TVs *before* it goes into the D->A
converter box, then it would be only digital - right?
Plain...@yahoo.com
wrote:
>Does there exist the opposite of an RF Modulator? Something that will
Phrase your question properly and you will get better results.
Google 'ATSC Modulator'.
PlainBill
Dave Platt
>>analog to all the tvs? I don't have the energy anymore to install
>>homeruns from the DVDR to any tv but the one in the same room. All
>>the rest are in series. I don't have the energy to run RCA cables for
>>composite or component.
>>
>>Can I convert the analog back to digital for the digital tvs?
>Phrase your question properly and you will get better results.
>
>Google 'ATSC Modulator'.
Probably unnecessary.
Almost all digital-cable TVs can receive and decode both ATSC
(digital) and NTSC (analog broadcast/cable) signals. They can look at
any proper 6 MHz slice of the broadcast spectrum, look at the signal
in that range, determine whether it's NTSC or ATSC, and display it
properly.
You can mix NTSC signals (e.g. the "channel 2/3" modulated output from
a VCR or DVD player) with ATSC digital, as long as you don't try to
put both on the same channel. The best way to do this is with a
proper single-channel combiner.
You ought to be able to arrange a setup which takes your incoming
antenna signal (which will consist almost entirely of ATSC signals),
buffers/amplifies it, mixes in a modulated NTSC signal from the DVDR
modulator (on a channel not used for ATSC), and distribues this out to
all of the TVs. Tune to an ATSC channel and they'll detect and decode
the corresponding digital signal. Tune to the channel you're using
for NTSC analog from the DVDR, and that's what they'll show.
This will be *much* less expensive than trying to take the analog
output of the DVDR, encode it into ATSC digital format, modulate it,
and mix it onto the cable.
The best video quality from the DVDR would be via HDMI (or component,
or S-Video, or composite, in that rough order) rather than via
modulated RF (which is often soft and blurry looking) but you'd need
home-run cables from the DVDR and some form of distribution amp to do
these.
--
Dave Platt <dpl...@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Jeroni Paul
> (digital) and NTSC (analog broadcast/cable) signals. They can look at
> any proper 6 MHz slice of the broadcast spectrum, look at the signal
> in that range, determine whether it's NTSC or ATSC, and display it
> properly.
Not around here. Digital only TVs are starting to proliferate since
analog TV is no longer broadcast, it makes little sense to pay for
obsolete technology any more. They only have Scart inputs, so if you
want to tune to VHF/UHF you will need an external analog tuner.
Plain...@yahoo.com
wrote:
Only if you are willing to settle for 'less than analog boradcast
quality signals'. Recall that anyone who compared the quality of the
RF signal output of a VCR to the composite signal quickly decided that
it was worth buying the composite cables. And a component connection
offers even better performance.
Also, unlike others, I do a little research. The last two DVD players
I purchased don't even have RF outputs. One, a Toshiba, DOES have an
HDMI output.
Doing a little research, the ZvBox� 170 appears to do exactly what
the OP proposed. Not surprising, that's what it was designed for.
PlainBill
UCLAN
>>The best video quality from the DVDR would be via HDMI (or component,
>>or S-Video, or composite, in that rough order) rather than via
>>modulated RF (which is often soft and blurry looking) but you'd need
>>home-run cables from the DVDR and some form of distribution amp to do
>>these.
>
> Only if you are willing to settle for 'less than analog boradcast
> quality signals'. Recall that anyone who compared the quality of the
> RF signal output of a VCR to the composite signal quickly decided that
> it was worth buying the composite cables. And a component connection
> offers even better performance.
>
> Also, unlike others, I do a little research.
Well try reading what is posted instead. It was stated that the best quality
video would be with HDMI, with component, S-Video, composite and RF trailing
in descending order. Correct statement. Not sure how your "boradcast" signals
would differ (if at all.)
Plain...@yahoo.com
It has been pretty well established that the best possible display in
a HDTV is with a Blu--Ray player and an HDMI connection. It goes
without saying that the HDTV must be capable of 1080P performance
(although all intelligent people agree that 1080I is pretty darn
close), with lower resolutions (of both the source signal and the
native resolution of the display) giving poorer results.
What is often ignored is the fact that an antenna that gives a good
signal and a broadcaster that does not limit their signal quality in a
number of ways (IE, broadcasting in 720P) will give a picture that is
ALMOST as good as Blu-ray. The chief deficiency is, of course, that
OTA broadcasts are either 1080I or 720P.
Given the OP's desire NOT to run additional cables, and a desire for
sharing top quality signals with all TVs, it thus follows that he must
use an ATSC modulator for each source and combine them onto the single
coax.
PlainBill
UCLAN
vjp...@at.biostrategist.dot.dot.com
*+-I believe they are only 1:1.
Ouch. Pet peeve.
I had learned to "design fan out of five", so I had a y-connector
using 2,3,8,20 RS232 pins for terminal and printer to modem. Then in
1983 I got an Epson computer, and they didn't support fan-out of
five. It was more like 150% instead of 500%.
THe Fan out of five equipment was all American made. So I never
bought the "Japanese quality" myth. (My family has been orginal owner
for twenty years each on five USA-made V8 cars built 1960-1980.)
- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]
Jim Yanik
news:htq3v8$a0r$4...@reader1.panix.com:
> *+-I don't know if those outputs are made to drive -multiple- sets.
> *+-I believe they are only 1:1.
>
> Ouch. Pet peeve.
>
> I had learned to "design fan out of five", so I had a y-connector
> using 2,3,8,20 RS232 pins for terminal and printer to modem. Then in
> 1983 I got an Epson computer, and they didn't support fan-out of
> five. It was more like 150% instead of 500%.
>
> THe Fan out of five equipment was all American made. So I never
> bought the "Japanese quality" myth. (My family has been orginal owner
> for twenty years each on five USA-made V8 cars built 1960-1980.)
I believe the outputs are 75 ohm impedance,a coax type transmission
line,that you can't drive parallel multiple 75 ohm loads.
It's not a matter of "fan-out".
Now if you had 75ohm loop-thru inputs like many professional video
units,then you just terminate the end unit in 75 ohms,and it would all work
fine.