Another Svideo to composite video prefilter

[benman94]

I built the previous pre-filter you had posted into my composite video adapter for my CT-100. Now I'll have to update ithe with this version. Thanks wa2ise!

[tubesrule]

What is the group delay distortion and return loss for this filter?

[wa2ise]

Originally Posted by tubesrule

What is the group delay distortion and return loss for this filter?

It gets to be +-100nsec, but most of that is in the skirt of the stopband. Which means that the frequencies with the severe group delay is also attenuated, so you won't see it.

[tubesrule]

Originally Posted by wa2ise

It gets to be +-100nsec, but most of that is in the skirt of the stopband. Which means that the frequencies with the severe group delay is also attenuated, so you won't see it.

Nice!

[wa2ise]

I took another look at the group delay, it's worse than I had remembered. I updated the diagrams above. About 250nsec for luma and 300nsec. However, the spectrum that would now be chroma only gets some group delay predistortion and thus it still looks okay on a TV set.
My other filter's frequency and group delay response:

And the circuit:
It's a tradeoff between frequency and group delay.
You'll have to decide which looks better.