Correct me if I am wrong here...
From reading the classicmac2 PDF in more detail, it looks like the video signal is a series of TTL pulses, but inverted, i.e., 1 = white and 0 = black. Hence, the inverter, U2. The horizontal sync signal is a series of TTL pulses that basically acts like a 22KHz oscillator and notes where the individual pixels are in the video data stream. The vertical sync signal is high while scanning from top to bottom, and low during retrace.
If this is correct, I should see something along these lines when connecting the three signals to an oscilloscope:
video: 100100101010110111 <- or whatever the pixel data for that scanline shows
h sync: 101010101010101010 <- continuous
v sync: 111111111111111111 <- until the last pixel, at which time it becomes 0.
Correct?
From reading the classicmac2 PDF in more detail, it looks like the video signal is a series of TTL pulses, but inverted, i.e., 1 = white and 0 = black. Hence, the inverter, U2. The horizontal sync signal is a series of TTL pulses that basically acts like a 22KHz oscillator and notes where the individual pixels are in the video data stream. The vertical sync signal is high while scanning from top to bottom, and low during retrace.
If this is correct, I should see something along these lines when connecting the three signals to an oscilloscope:
video: 100100101010110111 <- or whatever the pixel data for that scanline shows
h sync: 101010101010101010 <- continuous
v sync: 111111111111111111 <- until the last pixel, at which time it becomes 0.
Correct?