CIRCUIT FOR PREVENTING OSD TREMBLING IN TELEVISION RECEIVER

摘要

PURPOSE: A circuit is provided to prevent OSD(On screen display) trembling in a television receiver when received horizontal and vertical synchronizing signals have a gap between them at a starting point. CONSTITUTION: The circuit comprises: a first transistor(Q1) whose base terminal is connected to a horizontal synchronous signal input unit via a resistor(R2) and collector terminal is connected to a horizontal synchronous signal input terminal of a micom; a second transistor(Q2) whose base terminal is connected to a vertical synchronous signal input unit via a resistor(R4) and collector terminal is connected to a vertical synchronous signal input terminal; a power input terminal(5V) respectively connected to the collector of the first transistor via a resistor(R1) and to the collector of a second transistor(Q2) via a resistor(R3); a diode(D1) forwardly biased between the collector of the second transistor and a resistor(R1); and a condenser(C1) of which one end is connected in parallel between the collector of the second transistor and the vertical synchronous signal input terminal of the micom and the other end is grounded.