Journal ArticleDOI
A New Demodulation Method Improving FM System Interference Immunity
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TLDR
The improvement offered by the proposed demodulator is of such a degree that some of the important restrictions in planning different radio systems could be relaxed.Abstract:
As a result of investigation of interference into FM systems, a new algorithm for the process of demodulation is proposed. When compared to the method using the conventional limiter-discriminator, it offers better immunity against the baseband interference noise. Desired signal processing is performed by the functional devices added to the conventional limiter-discriminator in such a way that this new demodulator can be optimized in the sense of the minimum baseband interference noise. The statistics of the wanted and interfering signals must be known. Several examples involving interference problems in FDM-FM radio-relay systems carrying multichannel telephone signals are elaborated to illustrate the performances of the proposed demodulator. FDM-FM, PSK, or FSK systems are considered the cause of the interference. The noise power ratio (NPR) at the output of the conventional limiter-discriminator and the improvement factor offered by the new demodulator, obtained on digital computer, are presented versus baseband frequency in the form of diagrams. Different IF filters in FDM-FM receiver and transmit filters in the interfering systems are taken into account. The improvement offered by the proposed demodulator is of such a degree that some of the important restrictions in planning different radio systems could be relaxed.read more
Citations
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Dissertation
Novel adaptive array algorithms and their impact on cellular system capacity
P. Petrus,Jeffrey H. Reed +1 more
TL;DR: The theoretical capacity limit using an adaptive array at the base station for an AMPS cellular system is derived and a macrocell channel model which provides angle-of-arrival (AOA) statistics of the multipath components is provided.
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.
Book ChapterDOI
Modulation und Demodulation
TL;DR: In this paper, the authors present a Signalform, in which die Ubertragung der Nachrichten uber eine grostmogliche Entfernung unter Wahrung des erforderlichen Storabstands is gewahrleistet, wobei die spezifischen Eigenschaften des Uber tragungs mediums zu beruckichtigen sind.
Journal ArticleDOI
Study of adjacent and co-channel FM interference reduction
TL;DR: The reduction of FM interference caused by the reception of adjacent or co-channel signals is examined and methods where the residual interference is reduced independent of which signal is being demodulated, i.e. the normal FM capture effect is enhanced.
Reduction of transhorizon radio interference in satellite earth stations
TL;DR: In this article, the authors present a survey of the transhorizon propagation literature and its application in satellite-earth links, including a review of the current state of the art.
References
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Journal ArticleDOI
Spectra of digital FM
R. R. Anderson,J. Salz +1 more
TL;DR: In this article, the spectral density function of an ensemble of continuous-phase, constant-envelope FM waves is derived in terms of averages of elementary functions, and several of the specialized formulas are applicable in the study of multilevel FM data transmission systems as well as in pulse frequency modulation.
Journal ArticleDOI
Interference into Angle-Modulated Systems Carrying Multichannel Telephony Signals
TL;DR: An investigation of interference between angle-modulated systems carrying multichannel telephony, which is directly applicable to existing satellite and terrestrial radio-relay systems, has been undertaken and includes a general solution for arbitrary narrow-band interference into an angle- modulated system with arbitrary modulation.
Journal ArticleDOI
Interchannel interference considerations in angle-modulated systems
V. K. Prabhu,L. H. Enloe +1 more
TL;DR: It is shown that with band-limited white gaussian noise modulation (simulating modulation by a frequency division multiplex signal), an explicit expression for the spectral density of the baseband interchannel interference when two or more PM waves interfere with each other is derived.
Journal ArticleDOI
Spectral Characteristics of FDM-FM Signals
TL;DR: In this paper, the power spectrum of a sinusoidal carrier which is frequency modulated by a normally distributed baseband signal is expanded as a sum of weighted convolution terms, where the significant parameter in the expansion, for an ideally bandlimited baseband spectrum, is R{x}(0) = R{\dot{x}}(0)/f min f max where R{{x}) is the mean squared frequency deviation and f min and f max are the lower and upper frequency limits of the BS spectrum.
Journal ArticleDOI
Computation of Interference into Angle-Modulated Systems Carrying Multichannel Telephone Signals
TL;DR: A simple approach to calculate the convolution between the power spectra of the wanted FM signal and interference without direct calculation of the power spectrum of the FDMFM signal, which makes much simpler an accurate evaluation of the output noise power due to interference.