Temp. compensating bias source for VCO - uses avalanche diode and ordinary diode connected in series with input voltage and earth

摘要

A voltage controlled oscillator is for use in a phase locked loop where the VCO includes a constant current source means in addition to a current source varied by the control input signal to change the frequency of the VCO thereby providing a controlled tracking range. The constant current source means have a temp compensating bias source which includes a bridge cct where the bias voltage is taken from the center leg of the bridge which carries no current and thus produces no voltage level shift.