Unlock
Detector
@
Phase lock is obtained by use of the YTO (FM coil for ac corrections and main coil dc
corrections) which has a frequency tuning range of approximately
f20
MHz at 3 MHz/V
sensitivity.
Unlock detector U2 and associated circuitry is used to determine when the error voltage is
too large for the YTO Loop to respond. This detection is performed for both positive and
negative error voltages by U2A and U2B respectively.
If the error voltage (ramp output of Integrator
#2)
exceeds f6.1 V, control signal HULY
(High = YTO Unlocked) is generated and routed to the Al2 Front-Panel Interface where it
causes a service request to be generated. Coded information corresponding to this request is
placed on the Instrument Bus and is detected by the Al5 Controller which turns on the YTO
UNLOCK annotation on the CRT.
AllA
3