Comparison of various threshold modulation techniques used in pulse stuffing synchronizers

It is shown that the technique of pulse stuffing in synchronizers and the method of data compression in sigma-delta modulators (Σ-Δ ) are very similar in operation. In particular, it is identified that the conventional stuff threshold modulation and adaptive threshold modulation schemes used in digital communications are as same as the dithering and multi-loop architectures of sigma-delta modulators. Using the similarity between pulse stuffing synchronizers and Σ-Δ modulators, various alternative circuits that are suitable for jitter reduction in pulse stuffing synchronizers are proposed in the paper. The performances of these circuits, i.e. the use of multi-loop Σ-Δ modulators, higher-order Σ-Δ modulators, look ahead decision feedback (LADF) and multi-stage (MASH) Σ-Δ modulators are compared. It is shown that the performances of proposed alternative synchronizer circuits surpasses the performance of the conventional threshold modulation type jitter reduction techniques currently used in pulse stuffing synchronizers.