Electronically Tunable Square-Root Domain Filter Circuit

In this paper, electronically tunable square root domain low pass and band pass filter is designed by using state space synthesis procedure. A dummy DC input is added to state space equations in order to realize the filter. Natural frequency of the proposed filter could be tuned by varying the currents of the current sources. The designed filter is simulated in PSpice using TSMC 0.35 ¿m CMOS technology parameters. By varying the values of the current sources, the natural frequencies is swept for 2.95 MHz-8.31 MHz and 3.67 MHz-8.46 MHz, for band pass and low pass filters respectively. Also THD and noise analysis are simulated. The obtained simulation results are given.