Muting circuit

Abstract

Abstract PURPOSE:To eliminate a momentary increase in gain at the start of muting, by allowing a current by-pass transistor, constrolled by a mute signal, to operate in its unsaturation range. CONSTITUTION:Input signals (i) and (i ) supplied differentially are inputted to current Miller circuits Q1-Q4. Then, transistors Q10 and Q11 constituting a current by-pass circuit where their collectors are connected direct to emitters of output transistors Q2 and Q4, and forward diodies D1 and D2 which limit base input voltages are provided. Once a mute voltage is inputted, Q10 and Q11 try to conduct through buffer Q12, but since the base voltage is limited through the operation of D1 and D2, a current is absorbed without saturating. No variation in impedance viewed from Q2 and Q4 to Q10 and Q11 is caused, so that the gain of a current Miller circuit will greatly lessen without increasing.

Inventors

• 👤 Kazuo Watanabe
• 👤 Masanori Ienaka

Bibliographic Details