Patent ID: 6014177
Filing Date: 2000-01-11
Classification: H04N

Abstract:
A video display apparatus comprising a phase-locked loop receiving a horizontal synchronous signal for generating an oscillation signal following the frequency of said horizontal synchronous signal, a tracking circuit for generating a tracking control signal for moving a frequency of said oscillation signal into a predetermined capture range of said phase-locked loop when said frequency of said horizontal synchronous signal changes, so that said frequency of said oscillation signal follows said frequency of said horizontal synchronous signal, and an output circuit receiving and amplifying said oscillation signal to output a horizontal output signal, said tracking circuit including a switch circuit receiving said horizontal synchronous signal and said oscillation signal to supply said horizontal synchronous signal as a selected signal to said tracking circuit when the phase-locked loop is in an unlocked condition, and to supply said oscillation signal as said selected signal to said tracking circuit when the phase-locked loop is in a locked condition.