| 摘要 |
PURPOSE:To suppress the deviation of a gain at boosting and cut-off without use of an externally mounted resistor or the like by providing a shock noise prevention switch which is turned on only at the moment when the connection state of switches is changed and while the resistance ladder section is not in contact with the equalizer. CONSTITUTION:Each of a noninverting input terminal of a noninverting input amplifier connecting to an input terminal 1 and an inverting input terminal is connected to each resistance ladder section connecting to a resonance circuit section 9 respectively via a cut-off switch 8a/a boost switch 8b turned on/off by a control signal. On the other hand, a shock noise prevention switch 11 turned on only at the moment when the connection state of the switches 8a, 8b is changed and while the switches 8a, 8b are not conductive is provided to the equalizer, and the ladder section 7 connects to ground, thereby suppressing occurrence of minute deviation in the gain at boosting and cut-off with the constitution not requiring an externally mounted resistor or the like and with less number of components. |
