This article presents techniques for improving the distribution of the number of stack entries, for stack sequential decoding over a hard quantized channel, with emphasis on high rate codes. It is shown that, for a class of high rate b/(b+1) codes, a table-based true high rate approach can be easily implemented for obtaining a decoding advantage over the punctured approach. Modified algorithms, which significantly improve the distribution of the number of stack entries and decoding time, are proposed for rate 1/N codes and high rate b/(b+1) codes.

A computationally efficient modified Fano algorithm for decoding of convolutional codes, recently proposed by the authors [1] has been further studied through simulation. Computational efforts and the BER performance of the original Fano and the modified Fano algorithms have been compared for the i) BSC and ii) Rayleigh fading channel with flat fading assumption. For the simulation example, the performance of the modified Fano algorithm was found to be comparable to the Viterbi decoder.

For a matched filter correlator (MFC) required in a spread spectrum receiver, an active RC delay line has been developed and its performance evaluated. The building block of the delay line is a low pass type active RC filter with modifications to give desirable magnitude, phase and pulse response. An MFC processor for a bandwidth expansion of 15 in data communication application has been made using the RC delay lines and its experimental performance has been found to be close to the theoretical one.