The EL4583A extracts timing from video sync in NTSC, PAL,
and SECAM systems, and non-standard formats, or from
computer graphics operating at higher scan rates. Timing
adjustment is via an external resistor. Input without valid
vertical interval (no serration pulses) produces a default
vertical output.
Outputs are: composite sync, vertical sync, filter, burst/back
porch, horizontal, no signal detect, level, and odd/even
output (in interlaced scan formats only).
The EL4583A sync slice level is set to the mid-point between
sync tip and the blanking level. This 50% point is determined
by two internal sample and hold circuits that track sync tip
and back porch levels. It provides hum and noise rejection
and compensates for input levels of 0.5V to 2.0VP-P.