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

Volume

42

Issue

7

fYear

1994

fDate

7/1/1994 12:00:00 AM

Firstpage

2384

Lastpage

2389

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;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.297845

Filename

297845