PURPOSE: To make recording/reproducing of the sound of movies possible and prevent the degradation of the tone quality, by synchronizing a PLL with an input AC voltage and supplying the output as a clock to a PCM device.
CONSTITUTION: When a master clock MCK is supplied to a control pulse generator 31, various timing signals and control signals are formed and are supplied to a recording system 10 and a reproducing system 20, and recording and reproducing of audio signals for a VTR 200 are performed. In this case, the synchronization with a picture is performed synchronously with the power supply by a synchronizing circuit 40. The output of the circuit 40 is formed into a pulse through a filter 51 and a voltage comparing circuit 52, and this pulse is given to a PLL 60, and a signal synchronized with an input commercial AC voltage is supplied as the clock MCK to the generator 31 through a switch 55A, a PLL 56, and a switch 55B. As the result, the sound of movies are PCM-recorded/reproduced synchronously with the power supply.
YAMAUCHI HIROYUKI
SUETSUGU KENJI
