| 摘要 |
PURPOSE:To obtain a gain controller an output signal of which has no DC fluctuating component, by combining a differential amplifier circuit to which an input signal is supplied and two differential amplifier circuits to which a control signal is supplied. CONSTITUTION:The differential amplifier circuit to which the input signal Vin is supplied consists of transistors (TRs) TRQ11, Q12. Further, between each collector of the TRsQ11, Q12 and a power supply Vcc, two differential amplifier circuits comprising TRsQ13, Q14, and Q15 and two differential amplifier circuits comprising TRsQ17, Q18, and Q16 are provided respectively. Each collector of the TRsQ15, Q17, Q18 and each collector of the TrsQ16, Q13, Q14 are connected in common. Through the forming like this, the gain controller in the output signal of which no DC fluctuating component appears is obtained. |
