Hi everyone,

Just stumbled over an interesting thread!
Apparently, comb filters have evolved since the 1980s and became an alternative to RGB video and its drawbacks.

https://shmups.system11.org/viewtopic.php?f=6&t=43526

Not sure if that's about real, analogue comb filters, though.
The digital filter circuits may be very flexible, but are sometimes not quick enough.
I know this from RTTY filter converters and oscilloscopes. The digital stuff is not real-time enough.

PS: Another alternative might be a low pass filter that cuts off the harmonics and other noise.
I heard, in order to remove colour information (make a clean b/w signal),
3 MHz (low res graphics) or 3,5 MHz/4,4MHz (PAL) are used as cut-off frequencies for example.
https://retrocomputing.stackexchange.com/ques … omputer-and-fil