Study of a UHF Mobile Radio Receiver Using a Voltage-Controlled SAW Local Oscillator

Abstract

Abswuct-Voice-grade signal-noise-distortion (SINAD) tests have been made on a 422 MHz mobile radio receiver incorporating a SAW delay-line local oscillator controlled by a digital phase-locked loop. Details are given of in-channel tests showing required 12 dB SINAD performance with -109 dBm RF input into the antenna, as well as adjacent channel selectivity tests yielding required 70 dB SINAD selectivity at 25 kHz frequency spacing. General details of the receiver circuitry are also given, including the SAW local oscillator with steppedfinger delay line operating in the fifth-harmonic mode. Stability performance tests made with an automated frequency stability analyzer and Hadamard variance techniques, yielded a phase noise < -1 15 dBc/ Hz at 10 kHz Fourier frequency offset, in accordance with expectations. Frequency drift in the IF stage of the stability analyzer was typically in the order of 0.15 Hz over the measurement sequence.