Design of switched capacitor filter using bilinear transformation

Abstract

The authors describe a design approach of the SCF (switched capacitor filter) simulating the doubly resistively terminated LC filter which is based on the concept of the bilinear transformation. The design approach is experimentally confirmed by the measurement of a test circuit with discrete elements. The features of this design approach are as follows: the SCF structure is the same as that based on the LDI transformation, the SCF structure requires no sample and hold circuits at the front and back, and the aperture effect is approximately compensated. Consequently, the total circuit that includes the SCF, the prefilter, and the postfilter can become simple and small. This design approach is effective in the case of using the SCF with the prefilter and the postfilter on the same IC chip.<>