| 摘要 |
PURPOSE:To improve considerably S/N, wow and flutter, etc. in an audio output by driving a variable delay element of an audio signal system by driving a clock signal obtained by removing jitter contained in a video signal driving clock signal. CONSTITUTION:A circuit 21 for high frequency removal designed to remove and supply to VCO20 high frequency components of the output signals of VCO14 and VCO20 whose oscillation frequencies are changed for controlling the delay of a variable delay element 6 is provided between a variable delay element 6 and a VCO14. The high frequency removal circuit 21 acts equivalently as a low pass filter and is provided for removing high frequency noise, wow and flutter appearing in the audio output. The high frequency removal circuit 21 is composed of a phase comparator 22 for comparing the phases of the output clock signals of VCO14 and VCO20 and producing outputs corresponding to the phase difference, and a compensating amplifier 23 acting as a lowpass filter and supplying to VCO20 the phase difference signal from the phase comparator 22.
|
