How are the hsync and vsync signals encoded in the sync signal in a 15 KHz RGBS? I'm trying to view an old 8-bit computer with RGBS on an VGA monitor through an RGB to VGA converter. As it displayed a lot of noise on the margins, and also some blurred lines, I extracted the following waveform of the sync signal.
I'd say that the positive polarity pulses are the hsync and the negative ones, the vsync, as there are much more positive ones, but I'm not certain if this waveform is correct because I can't find how both signals should be encoded.
PS. Notice also the small pulse before transitioning to vsync (an indication of vsync?), and the 4 pulses of vsync (why 4? shouldn't be just one?)