Gyrator-based inductance equivalent in the input circuit of a radio receiver

Abstract

The paper presents a schematic of a radio receiver input circuit based on a gyrator. Formulas for resonance frequency and quality factor are derived, along with experimental graphs showing the dependence of these parameters on the values of passive elements in the circuit. Using transistors with a cutoff frequency of the current gain in a common-base configuration of about 200 MHz, the device achieves operating frequencies up to 4.5 MHz. Frequency tuning of the input circuit by nearly a factor of two can be accomplished with a resistor.