| 摘要 |
PURPOSE:To obtain excellent limiter effect against pulse noise with IC implementation simplified, by making it possible to vary the power supply of a differential amplifier according to a degree of modulation. CONSTITUTION:The limiter circuit consists of amplitude-limiting amplifier circuit 100, modulated-signal detection circuit 200, rectifier circuit 300, output bias compensating circuit 400, and constant-current-supply circuit 500. A DC voltage obtained by circuit 300 varies in proportion to the amplitude of modulated signal (ei) inputted to input terminal T1, namely, the degree of modulation, and is inputted to the base of power transistor Tr 113 of circuit 100 to increase a current value across Tr113, thereby acting as control signal Vc which controls input-output characteristics of differential amplification Trs 111 and 112, namely, the limiter level. |
