Journal ArticleDOI
Evaluation of a Method for Interference Control in Analog FM Systems
W. Aranguren,R. Langseth +1 more
TLDR
The method utilizes the fact that the desired signal has a nearly constant envelope; with interference present, the composite envelope becomes noisy, and a controlling processor measures this additional envelope noise, and iteratively adjusts the complex combining gain of an auxiliary signal to minimize the interference.Abstract:
We discuss a possible method for interference control in radio systems whose desired signal is analog FM. The method utilizes the fact that the desired signal has a nearly constant envelope; with interference present, the composite envelope becomes noisy. A controlling processor measures this additional envelope noise, and iteratively adjusts the complex combining gain of an auxiliary signal to minimize the interference. The expected residual interference remaining after minimization is proportional to the reciprocal of the square of the rms envelope fluctuation of the desired signal. This result was confirmed in a laboratory simulation of an intersecting radio route case using both large and small index FM. Beginning with signal-to-interference ratios of 30 to 40 dB, the controller increased these numbers to about 60 dB, the expected theoretical limit for a signal with 0.1 percent rms envelope fluctuation.read more
Citations
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Journal ArticleDOI
A new approach to multipath correction of constant modulus signals
J. Treichler,B. Agee +1 more
TL;DR: In this article, an adaptive digital filtering algorithm that can compensate for both frequency-selective multipath and interference on constant envelope modulated signals is presented, which exploits the fact that multipath reception and various interference sources generate incidental amplitude modulation on the received signal.
Journal ArticleDOI
New processing techniques based on the constant modulus adaptive algorithm
J. Treichler,M. Larimore +1 more
TL;DR: A real input, real coefficient version of the constant modulus algorithm is shown to perform arbitrarily close to the fully complex version, extended for the enhancement of signals having a nonconstant but known envelope, as might arise in data signals with pulse shaping.
Proceedings ArticleDOI
Adaptive co-channel interference cancellation and signal separation method
Y. Bar-Ness,H. Bunin +1 more
TL;DR: An adaptive method is proposed which improves these estimates and results in a better cancellation of interference, and is shown to be directly related to the cancellation quality.
Proceedings ArticleDOI
Co-channel interference suppression and signal separation method
Yeheskel Bar-Ness,H. Bunin +1 more
TL;DR: A method for interference suppression and signal separation of angle modulated signals is presented and the main idea is to use the amplitude variation of the composite signal to estimate the parasitic phase distortion incurred by the interferer.
Proceedings ArticleDOI
A multimode adaptive beamformer for quadrature-amplitude-modulated signals
R.P. Gooch,B.J. Sublett +1 more
TL;DR: The authors present the results of recent work on an adaptive beamformer designed to enhance the reception of N-state quadrature amplitude modulated (N-QAM) signal in the presence of multipath distortion and cochannel interference.
References
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Journal ArticleDOI
Adaptive antenna systems
TL;DR: In this article, a simple adaptive technique based on the least-mean-squares (LMS) algorithm is proposed to adjust the variable weights of a signal processor by forming appropriate nulls in the antenna directivity pattern.
Journal ArticleDOI
Application of Adaptive Arrays to Suppress Strong Jammers in the Presence of Weak Signals
TL;DR: It is shown that in an environment of one weak signal and one strong jammers, the adaptive array output suppresses the strong jammer below the weak signal by roughly the same amount that the jammer exceeded the signal before adaptation.