Building a Standards Converter

[ppppenguin]

Not surprised the decoder defaults to NTSC but can it be programmed to do otherwise? Possibly forced to PAL? If it gives an indication of absent input this can be used to switch to stored testcard. Simply ensure that its pulse outputs are not connected to the counters when input is absent.

Again this reinforces the great joy of programmable logic. If you encounter a problem like this it's easy to do a few trials to find a solution.

I have no idea about the modulator sound problem.