AMM & NS programme Complex Low - Pass Integrated Active Filter for Direct - Conversion Transceiver for

Project Abstract : Direct-Conversion is an alternative wireless transceiver architecture to the well-established super heterodyne, particularly for highly integrated, low power terminals. Direct-Conversion transceivers suffer from the imbalance of the I and Q paths. By using a complex low-pass filter topology instead of a conventional pair of real low-pass filters, this imperfection can be reduced. In this thesis, design of a 3.3V, fifth order complex Chebyshev gm-C low-pass filter for WCDMA transceiver is presented. The filter has a 3-dB cutoff frequency of 2.5 MHz and has been designed in 0.35μm CMOS technology. The designed filter has high input and output linearity, and good noise performance. On–chip automatic frequency tuning circuit has been designed to keep the filter frequency response immune to supply voltage, process and temperature variations. The designed frequency tuning circuit has a tuning error of less than 2%.