[QuadList] Ampex VR-1200 on ebay-in Apalachin, NY

[Chill315 at aol.com]

Don
 
The AFC and Bare Bones DOC were included in all the machines at some point  
in manufacture.  The DOC was part of the AFC design.  It was a freebie  as 
I put it.  The RF signal that was inserted back into the picture  during a 
drop out was the frequency of blanking.  This frequency was used  as it was 
the one that the AFC could clamp to a know point in the  video.  Ampex did 
not use sync for a good reason.  Sync levels varied  by a few between sources 
and thus with 100 IRE of video but different levels of  sync, the video 
level would change at the output of the de mod if you clamped at  sync tip prior 
to modulation.
 
At least this is the way that I understood.  Can someone verify this  or am 
I out to lunch on this theory?
 
Chris Hill
WA8IGN
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