DocumentCode :
1095845
Title :
Multichannel adaptive filtering for signal enhancement
Author :
Ferrara, Earl R., Jr. ; Widrow, Bernard
Author_Institution :
ESL Inc., Sunnyvale, CA, USA
Volume :
29
Issue :
3
fYear :
1981
fDate :
6/1/1981 12:00:00 AM
Firstpage :
766
Lastpage :
770
Abstract :
An adaptive technique for enhancing a signal against additive noise is described. It makes use of two or more input channels containing correlated signal components but uncorrelated noise components. The various input signals need not be of the same waveshape, since the adaptive enhancer filters the inputs before summing them. The output is a best least squares estimate of the underlying signal in a chosen input channel. Adaptivity allows optimal performance even though the signal and noise characteristics differ from channel to channel and are unknown a priori. Formulas for signal distortion and output noise power are developed. The more input channels available containing correlated signal components, the better will be the system performance. Excellent performance is obtained when the sum of the filter input signal-to-noise ratios (SNR´s), defined as functions of frequency, is large compared to unity at all frequencies of interest. In this case the output noise is small, the output signal distortion is small, and the output SNR is approximately equal to the sum of the filter input SNR´s. As such, the multichannel adaptive signal enhancer is a generalization of the classic time-delay-and-sum beamforming antenna.
Keywords :
Adaptive filters; Additive noise; Antenna arrays; Delay effects; Distortion; Frequency; Iterative algorithms; Least squares approximation; Signal processing algorithms; Signal to noise ratio;
fLanguage :
English
Journal_Title :
Acoustics, Speech and Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
0096-3518
Type :
jour
DOI :
10.1109/TASSP.1981.1163589
Filename :
1163589
Link To Document :
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