Title :
Cochannel FM interference suppression using adaptive notch filters
Author :
Rich, David A. ; Bo, Steven ; Cassara, Frank A.
Author_Institution :
AT&T Bell Labs., Allentown, PA, USA
fDate :
7/1/1994 12:00:00 AM
Abstract :
In this paper, a method of reducing cochannel FM interference with adaptive tracking notch filters, first proposed by E. Baghdady (1959), is refined and extended. Analytical descriptions and computer simulations of a novel adaptive notch filter are presented. The new form of adaptive notch filter is useful for suppressing strong cochannel FM and CW signals and allows simple, practical realizations of very high and adaptive notch filters in either analog or digital technologies. The analysis demonstrates that when the instantaneous frequency of the stronger interfering FM carrier signal is known precisely, the stronger signal can be completely eliminated. In some cases, placing an additional adaptive notch filter in front of the stronger signal demodulator to suppress the weaker desired cochannel signal improves the estimate of the stronger signal
Keywords :
adaptive filters; digital filters; filtering and prediction theory; frequency modulation; interference suppression; notch filters; CW signals; FM carrier signal; adaptive tracking notch filters; cochannel FM interference suppression; cochannel signal; computer simulations; instantaneous frequency; signal demodulator; Adaptive filters; Computer simulation; Demodulation; Digital filters; Frequency estimation; Frequency modulation; Interference suppression; Open loop systems; Phase locked loops; Signal analysis;
Journal_Title :
Communications, IEEE Transactions on
