Studies on a data communication system using digital matched-filter techniques Part II. Practical system†
SUBRAMANIAM AMBATI · International Journal of Electronics · 1974
A practical data communication system is built up for a pseudo-random binary signal based on m-sequence (PRBS) of length 15 bits as a PSK carrier. The complete construction of the binary PSK and ΔΣM-PSK systems are described for binary data transmission and the transmission of continuous information, respectively. The output signal-to-noise ratios of both the systems are measured separately for different input signal-to-noise ratios. The probability of error associated with the binary data transmission is also measured for different input signal-to-noise ratios. The theoretical and experimental results are reproduced. Comparison of these results with those of other equivalent PSK and FSK systems shows that this binary PSK system using PUBS carrier is highly efficient for binary data transmission compared to other equivalent PSK and FSK systems using sinusoidal carriers, since it has very small probability of error. For the transmission of continuous information, the optimized ΔΣM-PSK system has an SNR improvement of 15 dB/octavo. It is also shown that, by using PRBS as a wide-band carrier and digital matched filter as an optimum correlation receiver, this system can be operated with an input SNR of, as low as — 3 dB and, hence, has better noise-threshold characteristics compared to other equivalent RWM-PSK, f.m.-f.m. and ΔΣM-FSK systems. It is concluded that this ΔΣM-PSK system has better SNR characteristics than the equivalent RWM-PSK, f.m.-f.m. and ΔΣM-FSK systems.