What is PAL, NTSC, NICAM, HDTV?
Paul C Schlesselman
>Dear Sir/Madam,
> I always heard of those terms like PAL, NTSC, HDTV and NICAM.
> Can anyone tell me what they actually means and what is the
> principles behind them? Or you can reference some articles
> or books for me to read? ( I am equipped with basic knowledge
> of Signal processing).
> Thanks a lot.
> Please mail reply to : kl...@ie.cuhk.hk
I can shed a bit of light on this:
NTSC - National TeleVision Standards Committee
formed in the united states in the 1950s? to set standards for
color tv in North America / Caribbean
PAL - Phased Alternation Line
This is a German version of the NTSC system 50 HZ vs. 60 HZ
England and most of western and northern Europe use this
SECAM - french for ??? dont recall. but a technological improvement over
the NTSC PAL systems with no compatibility. delivers more
lines of resolution better chroma ect...
HDTV - High definition TeleVision
Nobody can seem to settle on a standard for this everyone is
headed in there own direction. If the U.S. settles on a standard
it will likely become the world standard.
NICAM - not familiar sounds like a japanese creation.
Check your library, or get on the internet to some online books or dial up
library catalogs for book ideas.
thanks yall
--
Ed Ellers
the real reason that PAL is so widely used is that (A) the Germans use it,
(B) most European countries chose PAL to stay compatible with Germany, and (C)
once that happened it made sense for the other 625-line countries to use the
same equipment.
SECAM stands (approximately) for "Sequential Color with Memory;" this French
system actually provides WORSE performance than NTSC or PAL in a number of
ways. The French use it because it was invented in France; the Soviets chose
it because it wasn't invented in Germany; the other countries that use SECAM
chose it instead of PAL because (at least at the time) they were allied with
the former Soviet Union or had strong economic ties to France.
HDTV is generally regarded as meaning a system with at least twice as many
scan lines as NTSC, or 50% more with progressive scanning.
NICAM (Near-Instantaneous Companded Audio Multiplexing) was actually developed
by the BBC and is the stereo TV broadcast standard in many 625-line areas (the
biggest exceptions are Germany, Austria and Switzerland). The actual broadcast
system is called NICAM 728 and delivers two 32 kHz/14-bit digital audio
channels; NICAM compression is also used for many non-broadcast applications
like the BBC's links from their studios to their TV transmitters, and has
actually been in use in those areas for over 20 years!
Irek Defee
>PAL - Phased Alternation Line
> This is a German version of the NTSC system 50 HZ vs. 60 HZ
> England and most of western and northern Europe use this
I see a lot of US bias here. This should be phrased as: NTSC was the
first primitive color TV system and PAL is much better TV color
system than NTSC :-). PAL has been adopted in many other places in the
world apart of Europe.
>SECAM - french for ??? dont recall. but a technological improvement over
> the NTSC PAL systems with no compatibility. delivers more
> lines of resolution better chroma ect...
French bias now ? :-). It is true that SECAM is an improvement over
NTSC, but PAL is better than SECAM ...
>NICAM - not familiar sounds like a japanese creation.
Huh, this is pure British creation: Near Instantanous Companded
Amplitude Modulation. NICAM is an acronym denoting digital stereo TV sound
system used in UK, Northern Europe, Spain and few other European
countries. This system gives practically CD sound quality, as far as
you can get it from optimization of 15 kHz bandwidth (32 kHz sampling rate) and
nonlinear 14-bit amplitude quantization to pack the sound signal into
0.75 Mbit/s bit stream. In Europe there is also another, analog stereo
sound system in use, most notably in Germany in neighbouring countries.
Irek Defee,
Signal Processing Lab.,
Tampere University of Technology,
Tampere, Finland.
Amritansh Raghav
In article <1993Nov6.1...@news.cs.tut.fi>, de...@cs.tut.fi (Irek Defee) writes:
|> In article <schless....@pv0241.vincent.iastate.edu> sch...@iastate.edu (Paul C Schlesselman) writes:
|>
|> >PAL - Phased Alternation Line
|> > This is a German version of the NTSC system 50 HZ vs. 60 HZ
|> > England and most of western and northern Europe use this
|>
|> I see a lot of US bias here. This should be phrased as: NTSC was the
|> first primitive color TV system and PAL is much better TV color
|> system than NTSC :-). PAL has been adopted in many other places in the
|> world apart of Europe.
MAJOR MAJOR U.S. bias :-)
India uses PAL and I am sure it has real primitive recording/broadcasting
equipment as compared to US T.V companies but the color is either better
or as good as the color here.
And anyways PAL because of swinging color burst does provide
more immunity to noise
Bob Myers
You may think that the original statement shows "U.S. bias", but it also
happens to be correct. The system selected by the NTSC for the U.S. standard
really WAS the first "compatible color" system. What we now call "NTSC" was
in fact derived from a proposal by RCA, and at the time (around 1950) was
one of three proposals being considered by the FCC - the other being a color
wheel (field-sequential color) system proposed by CBS, and a third proposal
from a group called CTI. The RCA system, which was very similar to the
final standard, relied on the then-revolutionary tricolor CRT.
Both PAL and SECAM followed the lines of the original RCA proposal, but
modified it to address what were seen as problems with this system; PAL
essentially IS identical to NTSC, with the minor modification of the phase
change on successive lines to better prevent some color problems. The rate
and resolution differences of PAL have nothing to do with the color encoding
scheme, and like the U.S. standard was chosen more for compatibility with
existing systems. (And please note that there ARE both a 525-line "PAL"
standard AND a 625-line "NTSC".)
This is all as should have been expected; in the first few years following
World War II, a rebuilding Europe had more important things to attend to then
developing a new entertainment broadcast standard. And anyone reading through
the history of the three standards will realize that there really WAS more than
a little politics behind the creation of SECAM; were these things decided
on a strictly technical basis, it is likely that PAL would have become the
standard for all of Europe and those countries which were then European
"colonies" or possessions.
We can only hope that a more sensible course is followed in selecting what
SHOULD be a single worldwide HDTV standard.
Bob Myers KC0EW Hewlett-Packard Co. |Opinions expressed here are not
Advanced Systems Div. |those of my employer or any other
my...@fc.hp.com Fort Collins, Colorado |sentient life-form on this planet.
Ed Ellers
proposed in 1949. RCA was simply(?) prposing to switch between R, G and B at
3.58 MHz; later they decided to only switch the low-frequency components and
sum the highs. After that, Hazeltine Research suggested adding a notch
filter to prevent the dots from being visible in the decoded image. Once that
happened, Hazeltine, Philco and others looked at the system and found that it
was very similar to what would be obtained by matrixing, and the first NTSC
system proposal was born -- against the wishes of RCA, which didn't join in
until late 1951.
Also, the 625-line NTSC system isn't used for broadcasting; the British and
Dutch favored it but ended up going to PAL instead.
Mark Callow
>
>Dear Sir/Madam,
> I always heard of those terms like PAL, NTSC, HDTV and NICAM.
> Can anyone tell me what they actually means and what is the
> principles behind them? Or you can reference some articles
> or books for me to read? ( I am equipped with basic knowledge
> of Signal processing).
> Thanks a lot.
>
Some amusing definitions:
NTSC - Never Twice the Same Color
PAL - Please All Lobbies
SECAM - Something Essentially Contrary to the American Method
In article <schless....@pv0241.vincent.iastate.edu>, sch...@iastate.edu writes:
> PAL - Phased Alternation Line
Actually it's "Phase Alternating Line"
> SECAM - french for ??? dont recall. but a technological improvement over
"Sequential Coleur Avec Memoire" (sequential colour with memory)
David Grieve
: NTSC - Never Twice the Same Color
: PAL - Please All Lobbies
: SECAM - Something Essentially Contrary to the American Method
Others for PAL are;
Peace At Last
(reflecting the in-fighting of the day).
Provocation ALlemand
("German Provocation" reflecting the French attitude of the day
to a German originated system)
Pay for Additional Luxury
(reflecting the cost of the delay line required).
...while in a humorous vein, another (unrelated) observation I heard
recently ..."the only platform on which Windows/NT runs well is a
35mm projector"....well, I enjoyed it :-)
David.
Killer
: : Some amusing definitions:
: : NTSC - Never Twice the Same Color
: : PAL - Please All Lobbies
: : SECAM - Something Essentially Contrary to the American Method
Or PAL = Picture Always Lovely (as opposed to NTSC)
Note that although colour shifts occur with NTSC whereas they are corrected
in PAL, when Americans come to our country they find the 50Hz flicker of PAL
rather annoying compared to their yucky colour 60Hz NTSC. Not really an
issue - just trivia.
--
--
Killer
cas...@elec.canterbury.ac.nz
__ ___
/ ` | ~ Some say my name is Peter
| | | but they are the ones you have
| __ |--- to keep an eye on.
\__/ o on. |___)ite me.............
{This sig is evolving. Disturbances are to be expected.}
Ed Ellers
The color shifts you're referring to are VERY rare these days; they're caused by
differential phase errors in the transmission chain, and once we got rid of the
AT&T microwave links that the U.S. networks used to use we basically eliminated
the ONE problem that PAL was invented to cure. My experience has been that when
American TV looks like utter hell -- as it often, BUT NOT ALWAYS, does -- it's
because someone screwed up somewhere in the transmission chain.
Until we get HDTV, I'll take NTSC over PAL any day -- it's easier to comb.
S S Sturrock
>
>Until we get HDTV, I'll take NTSC over PAL any day -- it's easier to comb.
So what causes the checker board patter to the edges of coloured regions on
NTSC? I have noticed this a lot with my multi standard TV when being driven
by NTSC LD you get a pattern of checks which move up the screen and when
you pause the CAV disc the pattern stops moving. I was in the US a couple
of weeks ago and wanted to see if this was an artefact of my TV but TVs in
the US do this too. In PAL mode there is no such effect with coloured
regions fitting the luma signal more accurately. Even more odd is the fact
that when I play an NTSC disc transcloded to PAL 4.43 525/59.94 the checker
board pattern goes away and I can actually see more detail in the image
than with pure NTSC. On the down side the colours are less rich in this
mode and for moving images pure NTSC looks better, but paused........
--
\. That is biological Captain! | Shane Sturrock, BRU, Darwin Building,
(}:-( -- Mr Sturrock | University of Edinburgh, Scotland,
/' | Untied Kingdom (Split now!) :-)
Cyrus Shafai
This is a question that has been bothering me for years.
I live in Canada, and I have been wondering why the picture quality on my
TV is noticably better for the Canadian channels in comparison to the
American channels. I have lived in Edmonton Alberta and Winnipeg Manitoba,
and this problem exists in both cities/provinces.
Let me expand on this statement.
My local cable company receives American Stations via a satelite link.
I assume something similar is the case for the Canadian stations.
If I watch a TV show which is shown on both a Canadian/American station, the
quality is the same. Which makes sence, since they both use the same
signal feed from an American network. The picture quality differnce only
exists if I watch a TV show which is exclusively produced/transmitted in
Canada. An example would be the evening news.
The quality differnce is in the sharpness of the picture. The picture
on Canadian stations seems to be sharper and seems to be made up of a
higher number of pixels; ie. seems to have a higher resolution.
Does anyone know of the reason for this? As far as I know, Canadian stations
use the same signal format at American stations. But I could very well be
wrong here.
-------------------------------------
Cyrus Shafai
Department of Electrical Engineering
University of Alberta
Ed Ellers
monitors -- the dots are "leftovers" caused by drastic line-to-line differences.
Since PAL is so much harder to comb cleanly most PAL sets use a notch filter
to take chroma out of the luminance path at the expense of some detail; if you
had both comb and notch filters in NTSC mode (as some sets in the U.S. do) you
wouldn't be seeing the dots.
As for the muted colors in the NTSC-to-PAL transcode mode, this may be caused
by misalignment of the transcoder -- it has to change the phase of the color
burst at the start of each line, and if that phase is incorrect a PAL monitor
will correct it and cut down saturation in the process. I've heard a lot of
reports of this problem with transcoding LD players.
Laura Halliday
for colour television in the world are indeed NTSC, PAL and SECAM.
This is very simplified (possibly over-simplified), but I think
closer to what the original poster was looking for...
All three systems take the three primary colours (red,
green, blue) and transform them into a YIQ signal, where the Y
channel is luminance (i.e. black & white tv). The I and Q
signals are sent on a subcarrier, with (very approximately) the
phase difference corresponding to a rotation around a colour wheel.
An NTSC signal (National Television Standards Committee) uses
quadrature amplitude modulation to put the I and Q signals on
the subcarrier. PAL (Phase Alternation by Line) does the same,
but on alternate lines an increasing phase shift corresponds to
going around the colour wheel in the opposite direction. SECAM
(a French acronym I don't recall offhand) sends the I and Q
signals on alternate lines, and the receiver uses the previous
line's I or Q signal to decode the colour information.
Each horizontal sync pulse contains a burst at exactly the
colour subcarrier frequency to keep the receiver in sync.
PAL bursts have a varying phase shift to tell the receiver
which direction the phase shift is on this line.
PAL's phase alternation means that small phase errors cancel
each other out on adjacent lines, with usually better picture
quality. Most countries that use PAL use 625 lines at
50 frames per second, but Brazil uses PAL with 525 lines,
60 frames per second. SECAM pictures can be good, but
by using the previous line's colour information there can be
aliasing on horizontal lines in the picture.
Since the primary feature of the transmitted video signal
is sidebands at multiples of the line frequency, the colour
subcarrier frequency is chosen so that it fits in between
sidebands. In NTSC System M the horizontal sweep rate is
15734 Hz and the colour subcarrier is at 227.5 times that,
or 3.579545 MHz.
There are various TV engineering handbooks out there that
can fill in details I've missed. And for country-by-country
details, it's hard to beat the World Radio TV Handbook.
High-definition TV is one of many systems that use higher
resolution than traditional TV systems, including the now-defunct
819 line system. Resolution greater than twice NTSC System M
(i.e. 1050 lines) is often a good rule of thumb. Some early analog
HDTV systems used 1125 lines, while modern digital systems
have yet to reach consensus.
...laura, VE7LDH
Ed Ellers
U.S. broadcasters. I don't have much experience with Canadian commercial
stations, but I've seen enough CBC stuff by satellite to tell that it is
definitely better. The same is true in Japan, which also uses NTSC.
Hal Stitt
>An NTSC signal (National Television Standards Committee) uses
>quadrature amplitude modulation to put the I and Q signals on
>the subcarrier. PAL (Phase Alternation by Line) does the same,
>but on alternate lines an increasing phase shift corresponds to
>going around the colour wheel in the opposite direction. SECAM
>(a French acronym I don't recall offhand) sends the I and Q
>signals on alternate lines, and the receiver uses the previous
>line's I or Q signal to decode the colour information.
(some technical stuff omitted)
>...laura, VE7LDH
Another expansion of the acronyms is also interesting:
NTSC = Never The Same Color
SECAM = Something Essentially Contrary to American Methods
PAL = Peace At Last
Hal.....
--
Hal Stitt hals...@netcom.com (619) 583-8240