Considerations of SNR improvement characteristics of the optimum linear filter of systems with signaldependent noises
Abstract
A new expression model for such signaldependent noises as shot noise and multiplicative noise which involves the introduction of a signaldependent index, n, is proposed. The optimum linear filter with respect to the signaltonoise (SNR) criterion is derived for transmission systems containing additive noise, some signaldependent noise, and intersymbolinterference. By assuming Gaussian input signal waveforms, SNR improvements by the optimum filter are obtained by way of numerical calculation. It is shown that the SNR improvement increases as the signaldependent index, n, of the dominant noise of the system increases; the improvement in intersymbolinterference here is large, and the optimum filter operates in such a way as to eliminate the dominant noise of the system first. In addition, it is shown that the SNR of the optimum filter varies according to the value of the standard deviation of a signal waveform and has a certain maximum value when the standard deviation varies under the constant signal energy. The advantages conferred by this filter are given quantitatively by comparing the SNR improvement characteristics with this filter with those of the full cosine rolloff filter.
 Publication:

Electronics Communications of Japan
 Pub Date:
 September 1983
 Bibcode:
 1983JElCo..66...73K
 Keywords:

 Channel Noise;
 Intersymbolic Interference;
 Linear Filters;
 Matched Filters;
 Performance Prediction;
 Signal To Noise Ratios;
 Fir Filters;
 Mathematical Models;
 Random Noise;
 Signal Transmission;
 Standard Deviation;
 Waveforms;
 Communications and Radar