Acoustic unit

  • Inventors:
  • Assignees: Toshiba Corp
  • Publication Date: December 08, 1979
  • Publication Number: JP-S54155752-A


PURPOSE:To make it possible to adjust a volume of sound to the best value to an ambient noise constantly by detecting the ambient noise of the acoustic unit such as a TV receiver by a sound-collecting microphone and by automatically adjusting the volume of sound of the acoustic unit depending upon the detection signal. CONSTITUTION:Sound-collecting microphone 5 detects a mixed sound of sound S of a TV receiver and ambient noise N and amplifier 6 amplifies the detection 5 signal up to the same level as S sent from amplifier 7 in the N=0 state and then send it to differential amplifier 8, where a sound signal in phase with S iutputted amplifier 7 is removed. The output signal of amplifier 8, namely, N has a large transient noise removed 9 through clip effect and is sampled by a gate signal from timing pulse generator 10, and it is passed through integrator 11 and operational amplifiers 12 and 14 to control the gain of TV sound circuit 17, so that the gain will be increased with large N while the gain is decreased with small N.




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    JP-2010102255-AMay 06, 2010Yamaha Corp, ヤマハ株式会社Noise estimation apparatus, calling apparatus, and noise estimation method