Automatic gain control circuit for amplitude modulator

Abstract

Abstract PURPOSE:To automatically control the gain of modulation circuit, by controlling mutual conductance of transistor located in the differential amplifying type modulation circuit in composition. CONSTITUTION:The block 4 is the blanced modulation section of multiplier type, and when the points P1, P2 are taken as the balanced output terminals of amplitude modulator, the carrier is not appeared by suppression. The block 6 is the constant current circuit consisting of transistors (TR)Q7, Q8 and Q9, and when the control voltage Vc is given to the terminal 9, the bias current indicated with Io is changed to change the mutual conductance of TRsQ5 and Q6. Since the gain of modulation circuit is proportional to this mutual conductance, the modulation gain can continuously be controlled with the control voltage Vc.

Inventors

• 👤 Tsuguo Otsuki
• 👤 Tadashi Yoshikawa
• 👤 Masao Takeda
• 👤 Kazuo Sato

Bibliographic Details