TV vertical sync. detector - uses transistor with capacitor in collector and constant current supply detecting vertical sync. from mixed signal

摘要

A detector circuit is used in TV systems for separating the vertical synchronisation information from a mixed horizontal/vertical sync signal. The detector is for use on the input of the vertical oscillator. The mixed signal to the output of the previous stage (1) is fed into the detector circuit (9) so that the pulse generator (10) is held in sync by output from the detector circuit. The power to the detector circuit (at 14) is from a constant current source in order to control the conditions across a capacitor (16) in the collector circuit of a transistor (13).