The application of semiconductors in a 860 mc radio receiver

Abstract

An all solid state, FM radio receiver operating at 860 mc is described. The active elements used are transistors and variable reactance diodes. The receiver is of the double conversion type with IF frequencies at 63 and 10.7 mc. The first local oscillator chain uses four stages to generate a signal at 923 mc. The crystal controlled oscillator and two frequency doublers use diffused base transistors. The output of the second doubler, at a frequency of approximately 300 mc, is then tripled in a circuit employing a varactor diode in order to obtain the desired local oscillator signal. The receiver has a 6 db bandwidth of 30 kc. If the output is equalized for a phase modulated signal, 10 db of noise quieting is obtained with a 0.8 microvolt input signal.