Head switching noise eliminating circuit

  • Inventors: SAKAI TETSUO
  • Assignees: Toshiba Corp
  • Publication Date: September 24, 1987
  • Publication Number: JP-S62217404-A


PURPOSE: To obtain excellent noise eliminating performance by a simple constitution, by sample-holding a demodulating output of a reproducing FM signal by a specific condition, and eliminating a modulated component generated by sampling, from its output signal. CONSTITUTION: A demodulated sound signal which is outputted from a demodulator 18 is applied to a sample holding circuit 31. A sampling signal S 8 of this circuit 31 is applied from a multiplying circuit 32. The circuit 32 multiplies an output signal S 5 of both the edge trigger circuit 20 and outputs the signal S 8 exceeding 40kHz. In this case, the signal S 8 is set so that a noise generating period becomes a high level. A signal which has been brought to sampling by the signal S 8 becomes a signal S 9 . The signal S 9 does not have a spectrum in a sound signal band generated by the head switching noise. Accordingly, by making the signal S 9 pass through an LPF 33 for eliminating the signal component exceeding 20kHz, the modulated component can be eliminated from the signal S 9 . In this way, the excellent noise eliminating performance is obtained. COPYRIGHT: (C)1987,JPO&Japio




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    JP-H0246570-AFebruary 15, 1990Nec Ic Microcomput Syst LtdDemodulating circuit