Error probabilites for a.s.k./p.s.k. systems in an additive mixture of Gaussian and impulsive noise

A simple expression for the error probability for coherent a.s.k/p.s.k systems in an additive mixture of Gaussian and impulsive noise is obtained. It is shown that the impulsive noise considered may, in certain situations, be treated as conditionally Gaussian. This allows the above error probability to be expressed a weighted sum of the error probabilities due to Gaussian noises of different noise powers.     

Performance degradation of two-link binary c.p.s.k. system incorporating direct phase regenerator

The letter presents an analysis for the bit error probability (b.e.p.) of a two-link binary coherent phase-shift-keying (c.p.s.k.) system corrupted by additive Gaussian noise and consisting of a direct phase regenerator (d.p.r.) followed by a coherent receiver. Equivalent signal/noise ratio (s.n.r.) degradations due to imperfections in a practical d.p.r. are evaluated at the 10?6 b.e.p. point.     

Error rate for p.s.k. and d.p.s.k. in the presence of source noise

The analysis of error rate in 2-level p.s.k. and d.p.s.k. systems has been extended to include the effects of source phase noise. Curves are presented for channel S/N ratios up to 6 dB and source phase deviations up to 0.6 rad r.m.s.     

Quantitative analysis of 2-f.s.k. traffic detection

Two different methods of detecting signal flow in a noncoherent 2-f.s.k. channel are analysed with respect to the necessary signal/noise ratio for a certain error probability. It is found that separate detection of each frequency requires s.n.r. ?18 dB compared to about 19.5 dB for sum detection when the error probability is 10?7.     

Error rate performance for s.f.s.k. with cochannel and intersymbol interference

The probability of error of s.f.s.k., with matched-filter detection in the presence of additive white Gaussian noise, intersymbol interference and cochannel interference has been studied. Results are presented as a function of the signal/interference ratio for a system using a third-order Butterworth filter.     

4-phase p.s.k. differential demodulator using a.s.w. delay lines

The letter describes a cheap and reliable solution, using acousticsurface-wave delay lines, for the differential demodulation of phase-shift-keyed digital signals at low digital rates (up to 20 Mbit/s). Results on 4-phase p.s.k. differential demodulators operating at 2.048 Mbit/s are reported in terms of bit error rate against energy per bit/noise spectral density ratio. In addition, using the same technology, a new multidifferential demodulator has been implemented. Owing to multiple differential demodulations carried out on the same signal, a significant improvement in both theoretical and experimental bit error rate is obtained.     

Error-rate measurements for s.f.s.k. with band limitation

The error rates of s.f.s.k. with matched-filter detection were measured under restricted bandwidth conditions. The Eb/N0 degradations from the ideal b.p.s.k. performance were determined as a function of the degree of band limitation. Results for both Gaussian and Butterworth filters are presented.     

Performance of multilevel d.c.p.s.k. system in the presence of both interchannel and intersymbol interference

A general model of a multilevel d.c.p.s.k. system is analysed in the presence of additive Gaussian noise, intersymbol interference and adjacent-channel interference. The symbol error probability is obtained by combining an analytical approach with a Monte Carlo simulation. Numerical results are presented as an example.     

Performance of a multilevel d.c.p.s.k. system in the presence of interference and Gaussian noise

Study of a multilevel d.c.p.s.k. system leads to the consideration of pairs of adjacent symbol vectors which depend on instantaneous levels. An analytic evaluation is made of symbol error probability for a general pair of such vectors in the presence of Gaussian noise.     

Generalised transient response of bandpass transfer functions to f.s.k.- and p.s.k.-type signals

A method that enables an accurate evaluation to be made of the instantaneous frequency response of bandpass filters is presented, and an explicit expression is derived for the general case of a constant-amplitude discontinuous-phase f.s.k. signal. Curves of responses of a 4-pole filter are included as an example, both for the continuous- and discontinuous-phase f.s.k. signal. A byproduct of this technique also permits the computation of the instantaneous phase and frequency response due to a p.s.k. signal.     

Bit error probability properties of Gray-coded m.p.s.k. signals

The bit error probability associated with the individual binary symbols is discussed for Gray-coded m.p.s.k. signals for large s.n.r.s. All Gray codes with uniform as well as with the most nonuniform bit error probability distribution are given for 16-phase signals; 8-phase signals and 32-phase signals are also considered.     

Error-detection in a d.p.s.k. system

It is suggested that, by a suitable choice of the differential phases in a d.p.s.k. scheme, not only the differential phases can be estimated at the receiver, but also certain errors can be detected. This result is based upon the reflected Gray-code relation satisfied by the signs of certain trigonometric functions.     

Error performance of frequency-hopped d.p.s.k. system

In order to accurately evaluate bit error rates for a frequency-hopped d.p.s.k. system, digital computer experiments were performed. The value of Eb/N0 at the 10?3 error rate without fading was 8.4 dB.     

Novel p.s.k. tanlock loop

A new loop for coherent demodulation of suppressed carrier phase-shift-keyed (p.s.k.) signals is presented. The p.s.k. tanlock loop (p.s.k.-t.l.l.) has a wider tracking range and faster phase acquisition than the Costas or squaring loops usually used for p.s.k. suppressed carrier tracking, but it has a greater tendency to false lock.     

Error performance of c.p.s.k. system in the presence of interference

The error performance of the c.p.s.k. demodulator using a decision-directed loop in the presence of c.w. interference is considered. Depending on the frequency of the interfering signal, different error-rate expressions are derived.     

Analysis of avalanche diode receivers by saddlepoint integration

The error probability in a binary fiber-optical communication system whose receiver utilizes an avalanche-diode detector is calculated by applying the method of numerical saddlepoint integration to Laplace inversion integrals for the probabilities of errors of the first and second kinds. It is shown how to choose the contours of integration for efficient numerical quadrature. The effects of shot noise, intersymbol interference, and additive Gaussian noise are taken into account, and the decision level on the receiver output is set to minimize the average probability of error. Examples show how the method can be used in receiver design to select system parameters such as the output pulsewidth and the sampling time in order to minimize the probability of error     

Improvements in coherent f.s.k. performance

It is shown that, provided that the phases of the mark and space frequencies are constant and satisfy a simple relationship, a filtered t.s.k. signal becomes a 2-phase p.s.k. signal, and may be coherently detected. Using a practical filter, the performance is within 2.2 dB of ideal p.s.k.     

Probability of Error Analyses of a BFSK Frequency-Hopping System with Diversity Under Partial-Band Jamming Interference--Part I: Performance of Square-Law Linear Combining Soft Decision Receiver

In this paper, error probability analyses are performed for a binary frequency-shift-keying (BFSK) system employingLhop/bit frequency-hopping (FH) spread-spectrum waveforms transmitted over a partial-band Gaussian noise jamming channel. The error probabilities for theLhop/bit BFSK/FH systems are obtained as the performance measure of the square-law linear combining soft decision receiver under the assumption of the worst-case partial-band jamming. The receiver in our analysis assumes no knowledge of jamming state (side information). Both exact and approximate (multiple bound-parameter Chernoff bound) solutions are obtained under two separate assumptions: with and without the system's thermal noise in the analyses. Numerical results of the error rates are graphically displayed as a function of signal-to-jamming power ratio withLand signal-to-noise ratio as parameters. All of our results, exact and approximate, indicated that the higher number of hops per bit produced higher error probabilities as a result of increased combining losses when the square-law linear combining soft decision receiver is employed in demodulating the multihop-per-bit waveform.     

Performance degradation of decision-directed c.p.s.k. demodulator due to uncompensated time delay of decision circuitry

The influence of the uncompensated time delay incurred in the nonoptimum symbol decision filter on the error performance of a decision-directed c.p.s.k. demodulator is considered. An iterative method for the probability of bit error computation is used.     

Influence of multipath fading in 4 ?-c.p.s.k. systems

The letter presents some analytical and numerical results relative to the performance of a 4?-c.p.s.k. system in the presence of additive Gaussian noise and of multipath fading represented by a two-ray model with random phase difference.