Nippon Telegraph and Telephone Corporation

Hitachi, Ltd.

Ntt Electronics Corporation

Yasunobu Inabe

Makoto Nakamura

Hideyuki Nosaka

Koichi Murata

Hiroyuki Fukuyama

Yoshitaka Sugawara

Masatoshi Tobayashi

Kimikazu Sano

Junjiro Kitano

Eisuke Tsuchiya

Tadakatsu Kimura

Masa-aki Tanabe

In an automatic gain control circuit, a peak detection circuit detects and outputs the peak voltage of an output signal from a variable gain circuit. An average value detection/output amplitude setting circuit detects the average value voltage of an output signal from the variable gain circuit, and outputs a calculated voltage. An amplification circuit controls the gain of the variable gain circuit by amplifying the difference between the output voltages of the peak detection circuit and average value detection/output amplitude setting circuit. The number of base-emitter junctions of transistors on a path in the peak detection circuit from input ports which receive output signals from the variable gain circuit to an output port which outputs a voltage to the amplification circuit is equal to the number of base-emitter junctions of transistors on a path in the average value detection/output amplitude setting circuit.

Automatic gain control circuit

A semiconductor switch circuit of field-drive type includes a bipolar component having forward blocking and reverse blocking junctions, and p-channel and n-channel IGPETS connected across the bipolar component so as to short-circuit its forward blocking junction. The switch circuit operates to turn on or off in response to the voltage signal to the gate circuit which is isolated from the bipolar component, irrespective of the polarity of a voltage applied across the bipolar component.

Semiconductor switch circuit

Growing community of inventors

Kanagawa, Japan

Yasunobu Inabe