PAL SIGNAL

I am doing a PAL signal generation project using atmega8.I need to know exact timing chart.ie Where do I give sync pulse,vertical pulse and other things??

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palli
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Google?

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martin

Reply to
martin griffith

I would say google for PAL timing should return plenty of hits and then depending on which country and type of PAL timing you are trying to match. PAL exists in many flavours from A to I and M for the main ones, some of the differences are to do with sound and transmission, others are to do with important things like sub-carrier frequency.

I personally would use a small CPLD for signal generation and not a micro in the first place.

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Paul Carpenter          | paul@pcserviceselectronics.co.uk
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Reply to
Paul Carpenter

Google is a good start, and also the Philips Video ICs : devices like teletext will have full PAL frame info.

I presume you do not want true PAL (colour information, phase encoded on the 4.433Mhz colour) : that's beyond a Mega8.

But just the composite sync signals, and some lowser frequency luminance should be do-able.

-jg

Reply to
Jim Granville

Paul Carpenter scrobe on the papyrus:

Not forgetting the very quaint PAL N, with three lines of equalising and serration pulses, as used in Uruguay & Paraguay!!!

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John B
Reply to
John B

Here's an example of such project:

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Reply to
Piotr Piatek

Paul Carpenter scrobe on the papyrus:

. .

Probably not PAL-M as that's 525. I was in the Thomson CSF studio in Rennes in the late 70's and it was PAL throughout with only a SECAM encoder on the studio output. The French control rooms had a style that even the Beeb couldn't match, so much space and the wonderful smell of coffee and croissants everywhere!!

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John B
Reply to
John B

Damn meant PAL-I .

Even though PAL-M is just plain weird.

Last I dealt with anything like that was late 80's and same then as to get equipment for SECAM then was so expensive for them. Even from French manufacturers.

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Paul Carpenter          | paul@pcserviceselectronics.co.uk
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Reply to
Paul Carpenter

Paul Carpenter scrobe on the papyrus:

. .

I think there were only two manufacturers of true SECAM mixers. Thomson and Cox. Thomson made a killing in Russia as they decided to go SECAM for some strange reason (probably something to do with arms trading no doubt) and Mike Cox would always go where no one else would dare to tread.

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John B
Reply to
John B

Probably also not American and not British, politics as well.

Until late 80's when it[1] became part of Abekas Video Systems, which in turn was part of Carlton Communications another Micheal, Micheal Green this time.

[1] Cox Electronics his company.
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Paul Carpenter          | paul@pcserviceselectronics.co.uk
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Reply to
Paul Carpenter

So SECAM studios really existed :-). I always had the (incorrect) impression that all studios were PAL and just transcoded to SECAM for distribution.

PAL was German and the relationship between West-Germany and Soviet Union weren't very good after the Berlin wall. Paying PAL royalties for the PAL patents to West-Germany would have been embarrassing.

While the Soviet dominated OIRT countries used the same 625/50i system as the EBU countries, the VHF channel assignment in OIRT System D was different from the EBU System B and especially the video-sound difference was 6.5 MHz while in EBU countries 5.5 MHz.

While the picture was receivable across the border, no sound was available on an ordinary receiver and hence the risk for "western propaganda" was reduced. In totalitarian states it was also much easier to control the availability of any standard converters (e.g. a

1 MHz oscillator and a mixer) to get the sound.

Using a different colour standard also forced viewers in OIRT countries to watch the programs in B/W, thus reducing the appealing of the neighbour country transmissions, when the transmissions from your own country could be viewed in colour.

Clearly the standard selection was political rather than technical.

Paul

Reply to
Paul Keinanen

As soon as I know the reason was technical. SECAM has much better immunity against distortion and noise while propagates over the pore radio channel.

I do remember when I had dual system VCR I use to keep all my favorite movies in SECAM just to keep the color unchanged, no matter how many times I watch them. While you make a copy with PAL you easily get color drops on some frames. It's not possible in SECAM - picture was crystal clear all the time.

Germany may end up with PAL decision because they were too small to care about signal quality in comparition with USSR with their thousand kilometers RF lines.

Seems you watch to much Fox News or 007 movies. TV standards were never been problem to sell Hollywood in Europe or Japan, even they hate it. The same thing for western propaganda in Warsaw block. US did that in SECAM.

Regards, Jon.

Reply to
tcpip

them.

This is strange, since the consumer video recorders do not record the composite signal, but instead separates the colour difference signals and store them separately from the luminance signals, which actually is stored on higher frequencies on the tape. Thus, it should not matter, if the original signal was NTSC, PAL or SECAM.

Paul

Reply to
Paul Keinanen

them.

Perhaps he isn't referring to consumer recorders? Our old helical Ampex recorders didn't separate chroma and luma.

Regards,

Michael

Reply to
msg

Paul Keinanen scrobe on the papyrus:

SECAM is an FM system for colour modulation and therefore doesn't suffer from the loss of amplitude of the colour subcarrier in the same way as a PAL or NTSC signal after multiple passes through a magnetic recorder.

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John B
Reply to
John B

On consumer VCRs, even the luminance is frequency modulated before being actually written to the tape.

Paul

Reply to
Paul Keinanen

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