[QuadList] WireLock Systems

[allanmc-avtech at comcast.net]

Phil,

Good refresher course in CT frame pulses.   Thanks for the reminder.

At the Washington CBS News Bureau we also locked to Rubidium.   But, I recall also there being times when we would go into a "WireLock mode" before feeding the Network.  My recollection was that the remote studio (Washington) would receive analog correction signals via AT&T lines from the Master Broadcast Studio (New York) to lock our sync generators to them.   Sounds beautiful!   However, I also recall some glitches with that system.  i.e., one night our Washington CR switcher took and put a 2" quad VTR deck on the line to the network before it was fully locked up.  Since the New York and Washington sync generators where WireLocked together,...the bump and grind of the two generator systems chasing each other was not a pretty sight.  Of course, it was a good system....assuming one avoided putting an unlocked tape deck on line!   But......XXXXX   happens!    Does anyone else remember the WireLock system?

Allan 




 -------------- Original message ----------------------
From: "Phillip G. Shaw" <pshaw at sitestar.net>
> Splices Technical:
> Editing on Quad:  The Control Track (240HZ) has a 30 HZ frame pulse recorded 
> (not to be confused with Color Frame) that the Capstan Servo uses to lock 
> the picture to the correct B&W Vertical field sequence.  This frame pulse 
> can be used to mechanically splice tapes together with a 50% chance you have 
> correct color framing. The result of a bad edit was a color flash at the 
> Edit. All tape machines used a Control track frame pulse to lock the servos, 
> that is why you can't edit the wrong "field" sequence.
> 
> 
> 
> The Machines don't much care about the Vertical interval after Equalizing 
> Pulses, this is the area housekeeping is done in NTSC .  The Edit timing 
> adjustment for quads was normally done on the Picture Monitor in pulse 
> cross, double punch input & demod  and adjust the "Hammer" (equal Pulses) 
> such that demod is delayed  ~ 50%
> 
> Trivia related:
> 
> The Grass Valley 300 Analog Switcher used line 15-16 for switch Clamping, 
> those that inserted VITC on that line were rewarded Glitches
> 
> 
> 
> Network Trivia:
> 
> The Color timing & phase of those times was sloppy but within the window of 
> the technology. In 1984 I was the Broadcast Systems design engineer for NBC 
> Political Conventions. The Locking Standard at that time was Rubidium (Rub) 
> that suffered a drifting figure eight error. The Field Guys would coordinate 
> with NBC-NY and be Wolf'ed ( NBC term used for adjusting) into phase (zero 
> beat).  The Sync Standards & distribution for CBC & ABC , of the Broadcast 
> Pool, became my responsibility. I meet with Engineering/operations of the 
> other network to find out how they accomplished phasing between them.
> 
> 
> 
> A) On Mondays NBC looked at CBS and adjusted thier NBC Rub's for a Zero 
> Beat.
> 
> B) On Wednesdays ABC looked at NBC and adjusted their ABC Rub's for a Zero 
> Beat
> 
> C) On Fridays CBS looked at ABC and adjusted their CBS Rub's for a Zero Beat
> 
> 
> 
> You can't make this stuff up & It worked
> 
> 
> 
> Phil Shaw
> 
> 
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