An accurate center frequency tuning scheme for 450-kHz CMOS G(m)-C bandpass filters

This paper describes a center frequency tuning technique for a second inter mediate-frequency (TF) bandpass filter, The utilization of the step signal response ensures the direct measurement of the center frequency. This tunin g technique guarantees the accuracy of the design. A 450-kHz G(m)-C bandpas s filter tuned using this technique has hen developed to integrate the TF m odule for personal digital cellular (PDC) handsets for use in 0.35-mu m CMO S, The filter with the tuning scheme achieves a center frequency accuracy o f +/-0.5%.