[time-nuts] Brooks Shera's GPS locking circuit II

[Brian Kirby]

Let me add a note.  The Shera controller also has a hold mode.  This 
mode will freeze the DAC output at its current voltage.  So when its 
engaged with a rubidium oscillator,  your rubidium becomes a normal 
unit, except it has been "super tuned" to UTC !  Short term specs return 
to normal, etc.

Somebody asked a question about the GPS sawtooth bridge and the 
controller.  If the controller detects a problem during the measurement 
period ( and remember it looks at the last value, the present value and 
the future value), it will throw out that solution, as it is not valid.  
It holds the last used value in the DAC. 
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