Hedghog L Standards Converter

[ppppenguin]

I've not experimented with PC derived 405 myself but it's obvious that the main problem is the non-standard syncs. This may not matter too much in many applications. In principle you can lock a decent source of 405 syncs (using TTL/CMOS, FPGA/CPLD or even a PIC processor) to the syncs from a PC. A PLL (a HC4046 will do) locked to H sync from the PC. Then divide down. NTSC subcarrier is easy that way too, as David Boynes has noted.

Then you can use a MC1377 as the coder or DIY with 1496 modulator chips as done in may professional designs including my own. A TBA520(?) works well as a coder too. It was part of the original Philips decoder chipset, with a pair of balanced modulators. A Labgear test pattern generator used it.