A versatile digitally controlled continuous-time filter structure with wide-range and fine resolution capability

A digitally programmable and reconfigurable filter structure is presented. The design is based on a versatile continuous-time biquadratic block realized by means of digitally controllable transconductance amplifiers and programmable capacitor arrays. A specific implementation, integrated in a 3 mu m p-well CMOS process, which is capable of synthesizing a large number of even-ordered transfer functions of up to sixth order with complete control of all pole pairs and zero pairs, is discussed. The programmable filter exhibits typical pole and zero resonant frequency resolution of +or-0.25% and typical bandwidth resolution of +or-0.5% over the three-decade adjustable range from 1 kHz to 1 MHz and features typical dynamic range of 60 dB.<
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