PURPOSE: To set the external gain freely, by modulation or demodulation of input signal every half cycle of carrier wave, and switching the output signal every half cycle of the carriers wave and negative feedback of demodulated or modulated signals to a modulation and demodulation section.
CONSTITUTION: Transistors (TR) Q1∼Q4 are in switching operation by carrier wave C fed to input terminals 1, 2, and the collector of TRs Q1, Q3 and TRs Q2, Q3 is grounded via resistors R1, R2, allowing modulated waves across the resistors R1, R2. This signal is amplified with a differential amplifier consisting of TRs Q15∼17 and Rs 16∼21, and is output from output terminals 6, 7. This modulated output is fed back to the emitters of TRs Q9∼Q12 via a differential amplifier consisting of TRs Q13, Q14. Further, the TRs Q9, Q12 and TRs Q10, Q11 are switched on and off with the carrier wave C alternately, then the fed-back modulation signal is multiplied with a switching function C (t) to produce demodulated signals across a resisror R8.
SUZUKI SHINJIROU
TAKEDA MASAO
TAKEKOSHI YOSHIO
