AM-FM RECEIVER HAVING IMPROVED BIAS SUPPLY CIRCUIT

摘要

AM-FM RECEIVER HAVING IMPROVED BIAS SUPPLY CIRCUIT The present invention relates to an AM-FM receiver of the superheterodyne variety having a novel bias supply circuit wherein a common filter capacitor may be used for the bias supply, the AGC function in AM operation, and the AFC function in FM operation. The B+ bias is supplied through a controllable current source which adjusts the bias in accordance with the detector output. In the FM mode setting, automatic frequency control of the local oscillator is provided by bias adjustment. In the AM mode setting, automatic gain control of the IF amplifier and of the AM section of the tuner is provided by bias adjustment. The invention has preferred application to integrated circuit fabrication.