Lock detector for AGC circuit used in TV receiver, monitor

摘要

The detector has a comparator (100) which receives an input reference signal (Vref) and a gain control input voltage (VOSCA). The comparator produces two logic signals (A,B). When the gain control voltage is within a set level, the values of the logic signals are within set levels and a logic signal comparator (COMP) outputs a signal to a memory (130) and a lock condition (Vlock) is recognised.