Effects of signal-dependant errors on the performance of switched-current Viterbi decoders

Analog current-mode circuits including switched-current (SI) methods can he employed beneficially to implement high-speed, low-power Viterbi decoders for convolutional codes. Unfortunately, signal-dependent errors due to charge injection tend to limit the application of these methods to relatively small constraint-length decoders. This paper presents a technique for reducing the effects of charge injection on system performance. As a result, the use of SI techniques can be extended to the realization of larger Viterbi decoders, including the type conventionally employed in satellite communications.