FM IF System

Intersil CA3089 is a monolithic integrated circuit that pro- vides all the functions of a comprehensive FM-IF system. The block diagram shows the CA3089 features, which include a three-stage FM-IF Amplifier limiter configuration with level detectors for each stage, a doubly-balanced quadrature FM detector and an Audio Amplifier that features the optional use of a muting (squelch) circuit. The advanced circuit design of the IF system includes desir- able deluxe features such as delayed AGC for the RF Tuner and AFC drive circuit, and an output signal to drive a tuning meter and/or provide stereo switching Logic In addition, inter- nal power supply Regulators maintain a nearly constant cur- rent drain over the voltage supply range of +8.5V to +16V. The CA3089 is ideal for high-fidelity operation. Distortion in a CA3089 FM-IF System is primarily a function of the phase linearity characteristic of the outboard detector coil. By Intersil Corporation