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 +/- 0.25% and typical bandwidth resolution of +/- 0.5% over the three-decade adjustable range from 1 kHz to 1 MHz and features typical dynamic range of 60 dB.