<title>Architecture-level center frequency drift compensation method for micromechanical filters used in IF stages of wireless telecommunication receivers</title>

Abstract

A prototype of a 433.92 MHZRF receiver using a micro- mechanical resonator as channel-selection filter in the 2nd IF stage has been realized (94.5 kHz center frequency, 20 Hz bandwidth). A novel approach is used for managing the temperature drift of the center frequency of the micro-mechanical filter. Instead of stabilizing the filter's center frequency by complex device-level and technological modifications (bias voltage tuning, mechanical or thermal compensation), we modified the architecture of the IF stage in order to continuously adapt the IF frequency to the filter's center frequency deviations. This is achieved by periodical real-time measurements of the filter's center frequency and by then generating the appropriate second LO frequency. The measurement of the center frequency is achieved by putting the filter in an oscillating closed loop. The measured relative matching error between the 2nd IF frequency and the filter's center frequency is better than 0.005%.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.