hi all I try to design circuit to do this job I have 4 cameras & I want to show all it's 4 images at the same time on the screen then I want regulate my steps 1- analysis of the pal system ( find the H&V sync. signals time)
2-calculate the new H&V sync. I want 3- design a circuit to replace the old H&V sync. signals with the new oneI want to do this job with very simple components not with pld or micro controller. is this procedure right or wrong ?
any help please
_If_ all you want to do is show the arithmetic sum of the four scenes on one screen and _if_ your cameras are genlocked then you can do this with a passive combiner and possibly some video buffers.
If you mean that you want to split the screen into four segments and display each of the four camera feeds into a different segment (or if you want the arithmetic sum and don't have genlocked cameras) then you need _way_ more than a PIC or other microcontroller.
The color and brightness of a spot on the TV screen is determined by the video signal at a certain time. To move the image around requires changing the timing. To make the image smaller requires drastic changes in the timing, and the selective deleting of some information.
Basically you'd need to capture the image digitally, field by field, into four separate buffers, mathematically zoom the images down by a factor of 2x, then read them out in one video stream. You'll need to do this in a way that doesn't lead to flickering, or to tearing or other motion artifacts in your reproduced video. The video standards are fairly challenging to get right, and the timing requirements are tight enough that you just won't get there with a microcontroller, even a fast
32 bit one. This is a job for serious digital logic. If there aren't chips out there already to do it you'll need at the least some moderately large FPGAs (or ASICs if your volume is high), video-grade ADCs, a good bit of RAM, and video RAM-DACs to make it work.-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
I would be surprised if there weren't. I work off and on for an infrared imaging company; for some reason no one makes an ASIC to take the signal from a cryogenically cooled detector and make it into good video (and FLIR has _good_ video).
So I'm not familiar with what's off the shelf, just how to take weird formats and convert them to analog video.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
I just had one of those 'duh' moments. Isn't what the OP wants to do the same task as PIP? None of the inputs are synchronous but the framestore takes care of that. It worked well on my '92 Mitsubishi. I don't have any chipsets in mind but they can't be too expensive since many analog TVs have them. GG
Wrong, as Tim suggests
look at the security TV CCTV market for quad splitters.
martin
On Sun, 11 Sep 2005 12:30:48 -0700, in sci.electronics.design Tim Wescott wrote: snip
I'm sure Philps do a chip set, with an incomprehensible data sheet to go with it
martin
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