A programmable band-select filter for digital IF software defined radio receivers

A new approach in designing the filtering stage in a digital IF-sampling software defined radio (SDR) receiver is presented. The proposed technique provides a practical solution towards the implementation of a programmable wireless transceiver compatible with the requirements of various voice and data wireless standards: TETRA, PDC, IS-95, GSM, IS-54, TACS and Extended GSM. A sixth-order 1 dB ripple Chebyshev band-pass filter is designed on standard 0.25 /spl mu/ CMOS processes to implement the IF filter. It is based on an operational transconductance amplifier (OTA) with large dc gain and wide bandwidth. The filter features high linearity and bandwidth programmability between 10 MHz and 35 MHz, at a center frequency of 100 MHz.