| 摘要 |
PURPOSE:To remove noise of large amplitude generated at the time of switching of a reproducing track by controlling the time of switching of the reproducing track by a horizontal synchronizing signal of a reproduced signal so that the integrated value of periodical noises becomes zero. CONSTITUTION:When a reproduced signal fetched from a magnetic recording medium 24 by a reproducing head 25 or 26 is supplied to a reproducing track switching circuit 29 after passing through a preamplifier 27 or 28, the reproducing track is changed by the reproducing track switching circuit 29. Out of the output signals of the circuit 29, only an FM voice signal component is extracted by a band-pass filter (BPF) 31 and demodulated by an FM demodulator 32. At the time, the integrated value of periodical noises generated by discontinuous FM voice signals at the time of switching of the reproducing track is phase- controlled so as to be zero by applying the leading edge of a reproduced synchronizing signal as a trigger input of a monostable multivibrator 37, so that the noises of large amplitude generated at the switching of the reproducing track can be removed without the deterioration of reproduced tone quality. |
