| 摘要 |
PURPOSE:To attenuate noise level at the time of silence by controlling an amplifier's gain by use of a reverse characteristic output signal for reproducing level of a tape recorder which is provided with an automatic recording level controlling circuit. CONSTITUTION:At the time of recording, if a recording and reproducing switch is turned to the R side, a signal from a mike 10 is automatically adjusted in accordance with an input signal and is recorded on a tape through a recording head 18 together with the bias from a bias oscillator 20. At the time of reproducing, if the switch is turned to the P side, the output of the reprducing head 18 is inputted to an AC amplifier circuit 30 and a logarithmic amplifier circuit 40 in which the signal is compressed when it is higher than a predetermined level. The compressed signal is converted to DC voltage and is inputted to a differential amplifier 34 which generates AGC control voltage of inverse characteristics for the input signal. |
