Frequency translated filter for a micro-miniature radio receiver

Abstract

A frequency translated filter adapted for integration into a conventional monolithic integrated circuit arrangement. The filter includes an RF amplifier having a gain determining port; a one port, AF (audio frequency), frequency selective, gain determining immittance network; a forced-commutated bridge of bilateral switching elements interconnecting the immittance network and the gain affecting port of the amplifier, and an RF local oscillator for providing a commutating drive signal to the bridge. The action of the RF commutating bridge is to convert the voltage and current appearing at the gain affecting port of the RF amplifier to a low frequency at the terminals of the AF immittance network, and to reflect the immittance of the AF network back through the RF commutating bridge, translating it up again in frequency. The effect is to permit the use of AF frequency selective elements to render an amplifier frequency selective at radio frequencies.

Dependencies are inferred from the claim text.