Synthesis of SIFO Electronically Tunable Log-Domain Universal Biquad

摘要

In this paper a synthesis approach for single-input-four-output(SIFO) universal log-domain biquad comprising lowpass (LP), highpass (HP), bandpass (BP) and lowpass/highpass notch(LPN/HPN) filtering functions is proposed. The approach was designed using log-exponential relationship between voltage and current of bipolar junction transistors (BJT). In order to verify the correct operation of the proposed universal log-domain biquad, the performance was evaluated through simulation results. The electronic tunability was verified by varying the bias current over several values. The independent tuning of the cut-off/centre frequency of LP/HP/BP and the notch frequency of LPN/HPN was also discussed. Also, the non-linearity behavior for all of the outputs was studied and the dynamic range for overall log-domain universal biquad was found as 38.3 dB.