What sync and pulse references are necessary for the Dual Sync Mode?
In the Dual Sync Mode, the TLC needs three signals. Primary sync reference is in the form of a 24 frame bi-level, analog sync signal. This signal looks exactly like a 625/50 sync reference except it has 24 frames (48 verticals), instead of 25. Sometimes this is called “Slow PAL”. The TLC will not lock to a tri-level sync reference. The Secondary or Alternate Reference to the TLC must be Vertical Drive from the locked 525/60 sync reference. The TLC only has one sync separator which is used for the 24 frame sync, so the Alternate sync must already be in the form of Vertical Drive. This may be either –2, -4, or TTL shaped sync. If TTL shaped, a slight modification to the TLC sync card will be necessary. This information is in the Technical Bulletin #52. The third signal is a 6 Hz Coincidence pulse. This is sometimes called a Field 1 Coincidence signal. This pulse is in the form of a positive going TTL shaped pulse no longer than one 60 Hz vertical. It should be greater than 4 or 5 ms and
