Automatic gain control circuit

PCT No. PCT/JP90/00915 Sec. 371 Date May 14, 1991 Sec. 102(e) Date May 14, 1991 PCT Filed Jul. 16, 1990 PCT Pub. No. WO91/01592 PCT Pub. Date Feb. 7, 1991.Automatic gain control of a communications receiver is provided by including a filter in the upper end thereof having a frequency pass-band which...

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Bibliographic Details
Main Authors SUGAWA; KATSUSHI, ENDO; KATSUHIRO
Format Patent
LanguageEnglish
Published 16.11.1993
Edition5
Subjects
BASIC ELECTRONIC CIRCUITRY
CONTROL OF AMPLIFICATION
ELECTRICITY
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Summary:PCT No. PCT/JP90/00915 Sec. 371 Date May 14, 1991 Sec. 102(e) Date May 14, 1991 PCT Filed Jul. 16, 1990 PCT Pub. No. WO91/01592 PCT Pub. Date Feb. 7, 1991.Automatic gain control of a communications receiver is provided by including a filter in the upper end thereof having a frequency pass-band which slopes off at each end and can be controllably shifted in a direction and by an amount determined by a control voltage which corresponds to the output signal level. As a result of such shifting of the frequency band relative to the frequency of a received signal, the filter provides adequate gain reduction even for unduly strong received signals and with less signal distortion and lower power consumption than occurs with AGC circuits which operate by changing the bias of a gain control amplifier. If the receiver employs a PLL with a voltage-controlled oscillator, the VCO control signal can be combined with the gain control voltage so as to control the center frequency of the filter pass-band as well as the amount by which it is shifted in order to provide gain control.
Bibliography:Application Number: US19910663955