The effects of digital implementation on ZePoC codec

This paper investigates the intrinsic problems of a digital implementation of a ZePoC Codec. We review the basic steps of a ZePoC modulator, showing its intrinsically analog nature. Then we evaluate the loss of performance of a digitally implemented ZePoC modulator, in terms of harmonic distortion within a certain low-pass band. To do this, we developed a fully analytical method to evaluate the effects of nonlinearities over quasiperiodic signals. Finally, an application of the analytical method were shown in an example. The example results suggest that, though ZePoC modulator is theoretically optimal, its digital implementation would unavoidably lead to a high loss in its performance.

[1]  F. Felgenhauer,et al.  Class-D audio amplifiers with separated baseband for low-power mobile applications , 2002, ICCSC'02. 1st IEEE International Conference on Circuits and Systems for Communications. Proceedings (IEEE Cat. No.02EX605).

[2]  A. Requicha,et al.  The zeros of entire functions: Theory and engineering applications , 1980, Proceedings of the IEEE.

[3]  Riccardo Rovatti,et al.  Spectral aliasing effects of PWM signals with time-quantized switching instants , 2004, 2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512).

[4]  J. Bartram,et al.  Digital Communication Systems , 1987, IEEE Journal of Oceanic Engineering.

[5]  B. F. Logan,et al.  Click modulation , 1984, AT&T Bell Laboratories Technical Journal.