Delay line adjustment for the optimization of digital continuous time filters

Systems which perform digital signal processing in continuous-time are attractive for a number of applications like biomedical implants, hearing aids, remote sensors, telecommunications, and audio and speech processing. While the inherent advantages of digital implementations with respect to programmability and noise immunity are retained by this kind of signal processing, they have some interesting advantages compared to classical sampled data systems. A main difference to sampled data systems is the realization of the delay elements which are implemented as quasi-continuous time delay lines. In this paper, it will be shown that an additional degree of freedom for adjusting the delay lines, and therefore optimizing the filter characteristic can be achieved for filter structures, well-suited for continuous time realization.