NTSC and PAL are making me confused!

[Myauk]

I am measuring CVBS outputs using NTSC and PAL playback discs with
Oscilloscope.
What are the differences between the NTSC and PAL CVBS output signals?
Will it be possible to say whether the CVBS signal is NTSC or PAL just
by examing the waveform at the Oscilloscope?
Regards

P.S it might be more appropriate to submit this question to
sci.electronics.repair or sci.electronics.basic but I am getting used
to be in this group!

 

[Damir]

I am measuring CVBS outputs using NTSC and PAL playback discs with
Oscilloscope.
What are the differences between the NTSC and PAL CVBS output signals?
Will it be possible to say whether the CVBS signal is NTSC or PAL just
by examing the waveform at the Oscilloscope?

No.The main difference between PAL and NTSC is how the color
information is coded and decoded.

Regards,
Damir

 

[Jan Panteltje]

I am measuring CVBS outputs using NTSC and PAL playback discs with
Oscilloscope.
What are the differences between the NTSC and PAL CVBS output signals?
Will it be possible to say whether the CVBS signal is NTSC or PAL just
by examing the waveform at the Oscilloscope?
Regards

One immediate thing you notice is that NTSC has 60Hz frame rate,
and PAL 50Hz.
The second thing is that I think NTSC uses a 'setup' in black,
and PAL does not (you can see that if if you display a horizontal line).
So black is actually not at blanking level, but a few percent above it.
Then there is the color burst, it changes 90 degrees phase each line.
You can see that on a H triggered scope.

 

[Ban]

I am measuring CVBS outputs using NTSC and PAL playback discs with
Oscilloscope.
What are the differences between the NTSC and PAL CVBS output signals?
Will it be possible to say whether the CVBS signal is NTSC or PAL just
by examing the waveform at the Oscilloscope?
Regards

P.S it might be more appropriate to submit this question to
sci.electronics.repair or sci.electronics.basic but I am getting used
to be in this group!

Switch your scope to TV-frame/field-sync and measure the time between each
half_field, 16.7 vs. 20ms
If your scope doesn't have this trigger feature you probably won't be able
to determine the format.

 

[Damir]

One immediate thing you notice is that NTSC has 60Hz frame rate,
and PAL 50Hz.

NTSC could also be with 50Hz frame rate and 4.43MHz color carrier.
The difference between NTSC and PAL is in the way U and V signals
are included in two horizontal lines.

 

[Roger Hamlett]

NTSC could also be with 50Hz frame rate and 4.43MHz color carrier.
The difference between NTSC and PAL is in the way U and V signals
are included in two horizontal lines.

Yes. and you can also get PAL at 60Hz.
The frame rate, is a good 'guide', for where to start looking, but should
not be taken as gospel.
This is the best simple test. It is after all, the 'core' of PAL (phase
alternation by line).

Best Wishes

 

[Eeyore]

No.The main difference between PAL and NTSC is how the color
information is coded and decoded.

Is NTSC ever 50 fps ? I thought it's always 60.

And is there ever 60fps PAL ?

Graham

 

[[email protected]]

Yes, they do have PAL-60 (60 fields/sec) - never seen any NTSC-50 fps

 

[Michael Black]

"Myauk" ([email protected]) writes:

P.S it might be more appropriate to submit this question to
sci.electronics.repair or sci.electronics.basic but I am getting used
to be in this group!

And that's the problem, problem posting here because it's their "hang out"
instead of finding the appropriate newsgroup.

Up until late 1995 (or was it '96? it's been so long I can't remember)
there was only sci.electronics and sci.electronics.repair Traffic was
heavy, at least for some, so some decided to split it up into multiple
newsgroups. The vote passed, and we have the multiple newsgroups in
the hierarchy that you see today.

But all of that goes to waste when some fool decided they should post
a basic question in sci.electronics.design because "they like it there".
Likely that fool shouldn't have been posting there in the first place,
because their questions were basic to begin with.

If you can only come up with a vague quesiton, then your question belongs
in sci.electronics.basics Or better yet, start reading some books that
are the time honored way to learn. Then come up with some detail that the
book doesn't answer, or doesn't explain well, and use sci.electronics.basics
to ask a question that will get an asnwer that fills in the missing detail.

Your question is about laziness, because there is no indication that you've
done any reading to see any difference between the two systems. If you
hd, then you'd be specific about what they have in common, or not have
to ask the question as you realize they aren't really different.

I should also point out that when you ask a basic question here, you
often won't get the best answers, because nobody is taking your beginner
status into the equation.

Michael

 

[Frank Raffaeli]

instead of finding the appropriate newsgroup.

Up until late 1995 (or was it '96? it's been so long I can't remember)

[rant with no answer snipped]

Which PAL or NTSC version (which countries) do you care about? It may
be as simple as checking the frame rate, as Ban pointed out.

If you view the color burst on a scope sychronized to and triggered by
the Hz line rate, you will generally see +/- 90-degrees phase shift in
PAL (on alternate lines) and 180 degrees on alternate fields. So: 90,
180, 270 and zero

In NTSC, you will observe only the 180 degree shift. All this presumes
sc/hz phase lock at the source, as with a broadcast signal.

Frank Raffaeli
http://www.aomwireless.com/

 

[Frank Raffaeli]

instead of finding the appropriate newsgroup.

Up until late 1995 (or was it '96? it's been so long I can't remember)[rant with no answer snipped]

Which PAL or NTSC version (which countries) do you care about? It may
be as simple as checking the frame rate, as Ban pointed out.

If you view the color burst on a scope sychronized to and triggered by
the Hz line rate, you will generally see +/- 90-degrees phase shift in
PAL (on alternate lines) and 180 degrees on alternate fields. So: 90,
180, 270 and zero

In NTSC, you will observe only the 180 degree shift. All this presumes
sc/hz phase lock at the source, as with a broadcast signal.

Frank Raffaeli

http://www.aomwireless.com/

sonofagun ... the color burst is not +/- 90 degrees wrt the horizontal,
it's +/- 45 degrees
Frank

 

[Jim Backus]

What are the differences between the NTSC and PAL CVBS output signals?

The colour sub-carrier frequency. 3.5... MHz for NTSC, 4.3... MHz for
PAL My solution would be to look with a spectrum analyser and see what
frequency the sub-carrier was.

 

[jasen]

I am measuring CVBS outputs using NTSC and PAL playback discs with
Oscilloscope.
What are the differences between the NTSC and PAL CVBS output signals?
Will it be possible to say whether the CVBS signal is NTSC or PAL just
by examing the waveform at the Oscilloscope?
Regards

yes. the differences in frequency of the different components of the signal
should make hint at that.

othewise you would have to look at the intelligence in the signal
(if you pick the right encoding you'll see pixels of the similar
colour clustered together)

Bye.
Jasen

 

[jasen]

instead of finding the appropriate newsgroup.

Up until late 1995 (or was it '96? it's been so long I can't remember)

[rant with no answer snipped]

Which PAL or NTSC version (which countries) do you care about? It may
be as simple as checking the frame rate, as Ban pointed out.

stick a NTSC tape in a multisystem VCR and the output will be PAL at the
NTSC framerate. (no doubt, with significant jitter)

Bye.
Jasen