Hi Jeffrey
That sounds like a good plan it should work.
Before I settled on counting the pulses between the broad pulses there was another way of detecting the field sync that I was thinking about but didn't try.
It uses an accumulator and went something like this.
Separate the syncs by slicing. If Video level > 30 then slice < = '1'.
For every cycle slice = '1' and the accumulator > 0 then take 1 away from the accumulator.
For every cycle slice = '0' then add 1 to the accumulator.
Assuming 864 cycles per line.
After line sync pulse the maximum in the accumulator should be no more than 100.
After a string of 8 broad pulses the accumulator should peak at around 2000.
To allow for any rubbish in the sync area a threshold of something like 1800 could be set for a valid field pulse at which time the accumulator would be reset to 0.
It's was just an idea I never tried it.
Frank
That sounds like a good plan it should work.
Before I settled on counting the pulses between the broad pulses there was another way of detecting the field sync that I was thinking about but didn't try.
It uses an accumulator and went something like this.
Separate the syncs by slicing. If Video level > 30 then slice < = '1'.
For every cycle slice = '1' and the accumulator > 0 then take 1 away from the accumulator.
For every cycle slice = '0' then add 1 to the accumulator.
Assuming 864 cycles per line.
After line sync pulse the maximum in the accumulator should be no more than 100.
After a string of 8 broad pulses the accumulator should peak at around 2000.
To allow for any rubbish in the sync area a threshold of something like 1800 could be set for a valid field pulse at which time the accumulator would be reset to 0.
It's was just an idea I never tried it.
Frank
