A tunable duty-cycle-controlled switched-R-MOSFET-C CMOS filter for low-voltage and high-linearity applications

A switched-R-MOSFET-C filter with tunable corner frequency is described. The tunability is achieved by varying the clock duty cycle using an automatic tuning circuit. This tuning method does not involve a change in any gate voltage, and is therefore particularly suitable for low-voltage and high-linearity applications. The advantages of the proposed method are illustrated with the design and simulation of a high-Q biquad filter.