Tuned radio frequency amplifier with back to back varactor diodes connected through a common cathode lead

摘要

A tuned radio frequency amplifier includes signal amplification means having an input and an output and first and second pairs of varactor diodes, each pair having an inductor connected across the anodes and a common tuning voltage supplied to the common cathode. The inductor of the first varactor diode pair provides an input for a signal from an antenna; and the inductor across the second varactor diode pair provides an output for the amplified signal. Means are provided for connecting the input of the signal amplification means to the common cathode of the first varactor diode pair and the output of the signal amplification means to the common cathode of the second varactor diode pair, whereby the range of tuning voltage required for a specified range of tuned frequencies is smaller than if the input and output of the signal amplification means were connected across the anodes of the varactor diode pairs.