automatic phase control


automatic phase control

[¦ȯd·ə¦mad·ik ′fāz kən‚trōl] (electronics) Abbreviated APC. A circuit used in color television receivers to reinsert a 3.58-megahertz carrier signal with exactly the correct phase and frequency by synchronizing it with the transmitted color-burst signal. An automatic frequency-control circuit in which the difference between two frequency sources is fed to a phase detector that produces the required control signal.