Intermediate frequency filter calibration method for radio frequency receivers in modern CMOS technologies

In this paper an intermediate frequency filter calibration method for radio frequency receivers has been presented. The method allows calibrating bandwidth of low-pass filters and center frequency of band-pass filters. Most of the calibration process is done in the digital domain and only one analogue buffer and one multiplexer are necessary. The presented method calibrates directly the filter that is actually in the signal path. The benefit of this method is that no filter replica is needed and only a small part of the calibration circuitry has to be placed near the filter. Moreover, problems with mismatch between the filter replica and the actual filter are avoided. The method was implemented as a part of the multi-standard GNSS receiver implemented in UMC 130 nm CMOS technology.