Studies on a data communication system using digital matched-filter techniques Part I. Theoretical investigations†
SUBRAMANIAM AMBATI · International Journal of Electronics · 1974
The mathematical analysis on which this data communication system is based is developed. For binary data transmission, a binary PSK system is developed in which the waveform corresponding to binary data is modulated onto a PSK signal (a r.f. carrier) consisting of pseudo-random binary signals (PRBS) bused on m-sequences. The optimum detection of the binary data in the presence of an additive white noise, by the digital matched-filter receiver, is investigated on analogy with the system identification (pattern-recognition) technique. For the transmission of continuous information over a noisy channel, an optimized ΔΣM-PSK system is developed, in which the continuous signal is first converted into binary waveform by delta-sigma modulation and this binary waveform is then modulated onto a PSK signal consisting of PRBS based on m-sequences. The receiver for this system is a digital matched-filter (PSK detector) followed by a ΔΣM decoder. The expressions for the output signal-to-noise ratios of the binary PSK and the optimized ΔΣM— PSK systems are also established. For the binary PSK system, the output SNR is found to be proportional to the length of the pseudo-random m-sequence and is also independent of the transmission bandwidth. For the optimized ΔΣM—PSK system the output SNR is found to he proportional to tho fifth power of the transmission bandwidth and inversely proportional to the fourth power of the length of the pseudo-random m-sequence. An expression for the probability of error is also derived for threshold detection of the transmitted message data by the digital matched filter.