Showing papers on "Phase-shift keying published in 1971"

Multiple Error Performance of PSK Systems with Cochannel Interference and Noise

Abstract: The multiple error performance of a phase-shift-keyed (PSK) communications system, when both cochannel interference (due possibly to other cochannel angle-modulated systems) and Gaussian noise additively perturb the transmitted signals, is considered. The results are fairly general: the main requirement is that the interference be circularly symmetric. All of our findings are also applicable to the case when only noise is present. The results indicate that one cannot approximate well the effect of interference on the performance of a PSK system by treating it as additional Gaussian noise. First, we derive the probability density function f A of the phase angle of a cosinusoid plus interference and Gaussian noise. We then obtain readily computable expressions (in terms of f A ) for the probability of any number of consecutive errors in an m -phase system when either coherent or differential detection is utilized. For numerical results, the interference is assumed to be due to other cochannel angle-modulated communications systems, and the double error probability and conditional probability of error are given for 2- and 4-phase systems.

Phase-Ambiguity Resolution in a Four-Phase PSK Communications System

Abstract: The constraints of digital satellite communications systems have led to the derivation of a method for resolving the problem of recovered-carrier phase ambiguity in a coherent fourphase phase-shift-keying (PSK) communications system while simultaneously providing synchronization information. This method is described for the general case and a general implementation is given. In addition, implementations are given for two particularly simple special cases.

Error Probabilities Due to Impulsive Noise in Linear and Hard-Limited DPSK Systems

Abstract: A method previously presented by the authors for the evaluation of error probabilities in digital systems when impulsive noise is the main cause of incorrect decisions is here applied to differential phase-shift keying (DPSK) modems. Specifically, the receiver impulsive characteristic, which is proportional to the error rate, is evaluated for binary DPSK systems both in the linear and hard-limited modes of operation. Two encoding systems are considered, in-phase encoding and quadrature encoding, and it is shown that they yield essentially the same performance, at least when the binary symbols are equally likely. The results are compared with the performance of phase-shift keying (PSK) and it is found that, in the presence of impulsive noise, DPSK systems have, for the same SNR, an error rate which is nearly twice the error rate obtained for PSK. However, the dependence of error rate on SNR is generally a slowly decreasing function so that a considerable improvement in SNR is required to improve performance.

Comparison of several demand assignment multiple access/modulation techniques for satellite communications

Abstract: Comparison of demand assignment multiple access/ modulation techniques for satellite communication using high quality telephone channels

Comparison of Phase Tracking Schemes for PSK

Abstract: Introduction When transmitting data by symmetrical phase shift keying (PSK), the receiver must reconstitute the carrier which has been suppressed by the modulation. This can be done from the PSK signal itself, in which case there is an inherent ambiguity to be resolved, or alternatively an unmodulated carrier component can be transmitted, thereby degrading the achieveable Eb/No performance. It is presumed that carrier phase is derived from a tracking loop of finite bandwidth set by system dynamics; hence, the reference carrier reconstituted in the presence of additive noise is noisy. In addition, phase ambiguity due to slips in the tracking loop must be accounted for.