Continuous-time digital filters using delay cells with feedback

A novel delay cell using feedback is presented that reduces drastically the number of delay cells and die area needed for the realization of continuous-time digital (CTD) filters. As a proof of concept, the delay cells are used for the design of a CTD finite impulse response (FIR) filter with simulation results verifying its functionality. CTD-filters are asynchronous, therefore, handshaking logic are described to guarantee correct operation.