Providing a different video source to a LM1881 chip?

[thenimas]

In video electronics, people use a LM1881 chip to get sync from a composite video signal. It's an 8-leg chip that, when provided power, will output a Composite Sync channel when Composite Video is inputted. My question is, instead of inputting Composite Video, you input Sync-on-Luma? (the Y signal in S-Video).

I want to do this because, before the signal hits the chip, the Composite Video is much more prone to noise than Sync-on-Luma, and Sync-on-Luma is available for what I'm doing. Does it have to be Composite Video, or can I use Sync-on-Luma with this chip?

Diagram of the chip (not my photo):

 

[davenn]

Does it have to be Composite Video, or can I use Sync-on-Luma with this chip?

I don't see anything other than composite video mentioned in the datasheet
so the answer is probably no

 

[thenimas]

I don't see anything other than composite video mentioned in the datasheet
so the answer is probably no

The thing is though, all it does is take a signal and takes the sync out of it. I don't see what's so special about Composite that it's the only source that you can use.

 

[davenn]

The thing is though, all it does is take a signal and takes the sync out of it. I don't see what's so special about Composite that it's the only source that you can use.

well try it, maybe it will work
I'm just saying, other variations are not stated in the datasheet


Dave

 

[ramussons]

In video electronics, people use a LM1881 chip to get sync from a composite video signal. It's an 8-leg chip that, when provided power, will output a Composite Sync channel when Composite Video is inputted. My question is, instead of inputting Composite Video, you input Sync-on-Luma? (the Y signal in S-Video).

I want to do this because, before the signal hits the chip, the Composite Video is much more prone to noise than Sync-on-Luma, and Sync-on-Luma is available for what I'm doing. Does it have to be Composite Video, or can I use Sync-on-Luma with this chip?

Diagram of the chip (not my photo):

"Y is the luma signal, which carries the luminance – or black-and-white – of the picture, including synchronization pulses."
So, logically, one should be able to extract the Sync from Y using this chip.