Video signal conversion + PlayStation Multi A/V interfacin - Electronic Circuits Projects Diagrams Free

darkliquid · 22nd October 2004, 10:47 PM

Hi, I'm new here, but i've been reading the forum for a little while now.

Anyway, the project is this: I'm designing a telepresence system with a friend for my Uni project. The video system is quite complicated, and it turns out its going to be quite hard to do.

The video system kinda goes like this:

PAL Composite Video Camera on robot-->2.4GHz Transmitter-->2.4GHz Receiver-->PAL Composite Video Signal-->Olympus Eye-Trek FMD-20P VR Goggles

The goggle side of the system is designed to be self-contained and portable, so no access to a computer will be available for video signal conversion.

The trouble is, the goggles only take RGB with a composite sync. Having done some research, I have concluded that it will be very difficult.

There are plenty of IC's available that convert Composite->Digital RGB and then IC's that do Digital RGB->Analogue RGB, but these are complex to use SMD's and have fr more features that I require. I did find out that the V7021 IC's by Sony could serve my purposes, but alas, all the simple chips are discontinued and it seems that only these highly complex SoC's are available.

The complex chips I'm looking at are the Phillips SAA7114H and similar SAA711* IC's for input, the SAA7182 and similar for output or the Averkey AV250,AV251 for output. All these need a microcontroller to control them via I2C, which I can do using a PIC.

So, the question is, has anyone had any experience using any of these video processing IC's? I don't have the equipment at home or at college to confidently solder surface mount components like those chips, and I'd really rather avoid having to use them when so much of them will be going to waste anyway. Ideally, has anyone had any experience using the Sony V7021 and knows where I can get hold of some in the UK?

**mechie** · 25th October 2004, 09:29 AM

This may be useless info but ...
The old Microvitec Cub video monitors came with various input options, thes included RGB and composite. The service manual showed the 'add-on' PCB to accept composite and decode it to RGB.
Maybe finding a composite input Cub could be an alternative answer ?

**Nigel Goodwin** · 25th October 2004, 10:18 AM

What he needs is a 'colour decoder', best bet is to use an older chip (like the TDA3562), most modern TV's use larger chips which have many more functions incorporated in them.

Bear in mind, it will need a subcarrier crystal, luma and chroma delay lines, and a fair amount of support components.

darkliquid · 25th October 2004, 04:59 PM

Thanks for the information so far!

Actually, I have been investigating the TDA3561A and TDA3562A. They seem to be what I need.

I'm unsure what exactly I'll need for the support components you mention. Most of the stuff shown in the application section of the datasheets I can get hold of fairly easy, but the DL700 box it shows on the diagram seems to be very ellusive. I'm not exactly sure what it does, how it does it or even whether it is essential. Information on the practical usage of the TDA3561 and TDA3562 chips seems very rare.

I have an old TV or two I can hack open and hopefully get some info from, but any real information on exactly what I need to do to work out the various things I need to calculate seems few and far between. For example, information the 'sandcastle pulse' is very vague. I am assuming that (if it isn't an entirely separate sync signal used for some arcane function in the chip) that I can generate it from the composite signal itself, considering that is the only source of any signals I'll be getting. I also heard somewhere that it is a combination of the blanking and composite sync signals, but again this information is vague and unconfirmed. Could I grab the necessary signals I need to combine to form a 'sandcastle pulse' by using an LM1881?

Regardless, I've decided to go with the TDA3561 or TDA3562 (they don't seem very different at all).

What I need now is a good source of information on video signals and how TV signals, etc work. Can anyone recommend some good (and preferably cheap) publications or websites?

darkliquid · 1st November 2004, 08:14 PM

Okay, here is what I have so far.

http://www.darkliquid.net/media/proj...ess-design.png

Obviously, it isn't finsihed or even meant to be serious circuit, its more of a concept circuit of how a plan to more or less connect things and doesn't take into account quite how I'd connect them and what buffers and amps I'd then to use in order to do so.

If anyone has any info on video/TV technology or can point me to some links or books that would be useful that'd be a great help as so far I haven't found much in the way of definative information on how to extract all the signals I need from the composite signal, or quite what each signal does.

**Nigel Goodwin** · 1st November 2004, 08:31 PM

The DL700 is the chroma delay line, it provides a 64uS delay - it's probably the biggest difference between PAL and NTSC, and what cures most of the NTSC problems.

You can find one in most old TV's, more modern ones use a semiconductor delay chip.

darkliquid · 1st November 2004, 09:35 PM

Thanks for the info.

So essentially it does this more or less:

Code:

------|
      |
      |
      |---------
X------------>

becomes this:

   ------|
         |
         |
         |---------
X..X+64us-->

where X is the start of the waveform

If I'm right there, then I' gogin to have to find another method of creating that delay, preferably with simple, easily obtainable components as that DL700 seems exceedingly hard to find.

If you could point me in the direction of a suitable delay chip it would be most appreciated.

**Nigel Goodwin** · 2nd November 2004, 05:58 AM

Quote:

Originally Posted by darkliquid

If I'm right there, then I' gogin to have to find another method of creating that delay, preferably with simple, easily obtainable components as that DL700 seems exceedingly hard to find.

If you could point me in the direction of a suitable delay chip it would be most appreciated.

It's been a standard component for years and years, it should be easily available as a spare part. But even easier, take one out of an old TV set, that way you can get the required transformers as well.

BTW, they are usually blue or green.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

22nd October 2004, 10:47 PM
darkliquid New Member	Video signal conversion + PlayStation Multi A/V interfacin Hi, I'm new here, but i've been reading the forum for a little while now. Anyway, the project is this: I'm designing a telepresence system with a friend for my Uni project. The video system is quite complicated, and it turns out its going to be quite hard to do. The video system kinda goes like this: PAL Composite Video Camera on robot-->2.4GHz Transmitter-->2.4GHz Receiver-->PAL Composite Video Signal-->Olympus Eye-Trek FMD-20P VR Goggles The goggle side of the system is designed to be self-contained and portable, so no access to a computer will be available for video signal conversion. The trouble is, the goggles only take RGB with a composite sync. Having done some research, I have concluded that it will be very difficult. There are plenty of IC's available that convert Composite->Digital RGB and then IC's that do Digital RGB->Analogue RGB, but these are complex to use SMD's and have fr more features that I require. I did find out that the V7021 IC's by Sony could serve my purposes, but alas, all the simple chips are discontinued and it seems that only these highly complex SoC's are available. The complex chips I'm looking at are the Phillips SAA7114H and similar SAA711* IC's for input, the SAA7182 and similar for output or the Averkey AV250,AV251 for output. All these need a microcontroller to control them via I2C, which I can do using a PIC. So, the question is, has anyone had any experience using any of these video processing IC's? I don't have the equipment at home or at college to confidently solder surface mount components like those chips, and I'd really rather avoid having to use them when so much of them will be going to waste anyway. Ideally, has anyone had any experience using the Sony V7021 and knows where I can get hold of some in the UK?

25th October 2004, 09:29 AM
mechie Super Moderator	Cub monitor? This may be useless info but ... The old Microvitec Cub video monitors came with various input options, thes included RGB and composite. The service manual showed the 'add-on' PCB to accept composite and decode it to RGB. Maybe finding a composite input Cub could be an alternative answer ? __________________ I need a memory upgrade ... My head is full !

25th October 2004, 10:18 AM
Nigel Goodwin Super Moderator	What he needs is a 'colour decoder', best bet is to use an older chip (like the TDA3562), most modern TV's use larger chips which have many more functions incorporated in them. Bear in mind, it will need a subcarrier crystal, luma and chroma delay lines, and a fair amount of support components. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

25th October 2004, 04:59 PM
darkliquid New Member	Thanks for the information so far! Actually, I have been investigating the TDA3561A and TDA3562A. They seem to be what I need. I'm unsure what exactly I'll need for the support components you mention. Most of the stuff shown in the application section of the datasheets I can get hold of fairly easy, but the DL700 box it shows on the diagram seems to be very ellusive. I'm not exactly sure what it does, how it does it or even whether it is essential. Information on the practical usage of the TDA3561 and TDA3562 chips seems very rare. I have an old TV or two I can hack open and hopefully get some info from, but any real information on exactly what I need to do to work out the various things I need to calculate seems few and far between. For example, information the 'sandcastle pulse' is very vague. I am assuming that (if it isn't an entirely separate sync signal used for some arcane function in the chip) that I can generate it from the composite signal itself, considering that is the only source of any signals I'll be getting. I also heard somewhere that it is a combination of the blanking and composite sync signals, but again this information is vague and unconfirmed. Could I grab the necessary signals I need to combine to form a 'sandcastle pulse' by using an LM1881? Regardless, I've decided to go with the TDA3561 or TDA3562 (they don't seem very different at all). What I need now is a good source of information on video signals and how TV signals, etc work. Can anyone recommend some good (and preferably cheap) publications or websites?

1st November 2004, 08:14 PM
darkliquid New Member	Okay, here is what I have so far. http://www.darkliquid.net/media/proj...ess-design.png Obviously, it isn't finsihed or even meant to be serious circuit, its more of a concept circuit of how a plan to more or less connect things and doesn't take into account quite how I'd connect them and what buffers and amps I'd then to use in order to do so. If anyone has any info on video/TV technology or can point me to some links or books that would be useful that'd be a great help as so far I haven't found much in the way of definative information on how to extract all the signals I need from the composite signal, or quite what each signal does.

1st November 2004, 08:31 PM
Nigel Goodwin Super Moderator	The DL700 is the chroma delay line, it provides a 64uS delay - it's probably the biggest difference between PAL and NTSC, and what cures most of the NTSC problems. You can find one in most old TV's, more modern ones use a semiconductor delay chip. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

1st November 2004, 09:35 PM
darkliquid New Member	Thanks for the info. So essentially it does this more or less: Code: ------\| \| \| \|--------- X------------> becomes this: ------\| \| \| \|--------- X..X+64us--> where X is the start of the waveform If I'm right there, then I' gogin to have to find another method of creating that delay, preferably with simple, easily obtainable components as that DL700 seems exceedingly hard to find. If you could point me in the direction of a suitable delay chip it would be most appreciated.