scholarly journals Optimal nonlinear filtering of M-PSK signals against a background of harmonic interference with a random initial phase

2021 ◽  
Vol 9 (6) ◽  
pp. 46-56
Author(s):  
G. V. Kulikov ◽  
Trung Tien Do ◽  
E. V. Samokhina
Keyword(s):  
Initial Phase ◽  
Nonlinear Filtering ◽  
Noise Immunity ◽  
Signal To Noise Ratio ◽  
Radio Channel ◽  
Complete Suppression ◽  
Two Phase ◽  
Probability Of Error ◽  
Useful Signal ◽  
Optimal Nonlinear Filtering

Objectives. The widespread use of radio data transmission systems using signals with multiposition phase shift keying (MPSK) is due to their high noise immunity and the simplicity of constructing the transmitting and receiving parts of the equipment. The conducted studies have shown that the presence of non-fluctuation interference, in particular, harmonic interference, in the radio channel significantly reduces the noise immunity of receiving discrete information. The energy loss in this case, depending on the interference intensity, can range from fractions of dB to 10 db or more. Therefore, interference suppression is an important task for such radio systems. The aim of the work is to synthesize and analyze an algorithm for optimal nonlinear filtering of MPSK signals against a background of harmonic interference with a random initial phase.Methods. The provisions of the theory of optimal nonlinear signal filtering and methods of statistical radio engineering are used.Results. The synthesis and analysis of the algorithm of optimal nonlinear filtering of MPSK signals against the background of harmonic interference with a random initial phase are carried out. The synthesized receiver contains a discrete symbol evaluation unit, two phase-locked frequency circuits of reference generators that form evaluation copies of the signal and interference, and cross-links between them. Analytical expressions are obtained that allow calculating the dependences of the bit error probability on the signal-to-noise ratio and the interference intensity µ. It is established that uncompensated fluctuations of the initial phase of the useful signal have a greater effect on the receiver noise immunity than similar fluctuations of the phase of harmonic interference, especially with low positional signals.Conclusions. Comparison of the obtained results with the results obtained in the case when there are no harmonic interference compensation circuits shows that the use of the obtained phase filtering algorithms allows for almost complete suppression of harmonic interference. Thus, if µ = 0.5 and the probability of error is 10−2, the energy gain at M = 2 is about 2.5 dB, at M = 4 – about 6 dB, at M = 8 and M = 16 – at least 10 dB.

PROBABILITY OF BPSK SIGNAL RECEPTION ERROR IN PRESENCE OF SIMILAR HINDRANCE

2019 ◽  
pp. 55-59
Author(s):  
V. V. Zvonarev ◽  
I. A. Karabelnikov ◽  
A. S. Popov
Keyword(s):  
Initial Phase ◽  
Information Transfer ◽  
Radio Channel ◽  
Mutual Coherence ◽  
Coherent Noise ◽  
Probability Of Error ◽  
Discrete Signals ◽  
Average Probability ◽  
Correlation Receiver ◽  
Computer Type

The paper considers the problem of calculation of average probability of error of optimum symbol‑by‑symbol coherent reception of binary opposite phase‑shift keyed signals (BPSK) in the presence of similar synchronous noise. The noise similar to signal of PSK‑2 (BPSK), synchronous on clock periods, matching on frequency, differing in sequence of information characters and, perhaps, on initial phase of the bearing fluctuation is considered, up to mutual coherence of signal and noise. Formulas for calculation of probability of error are derived and results of partial computer type of diagrams of tension are given in some points of the correlation receiver. Optimum reception of discrete signals is carried out by means of the correlation receiver or the coordinated filter configured on signal in lack of noise in the presence of only receiver noises. It is shown that availability of synchronous similar or harmonious coherent noise, aim on structure, leads to decrease in noise stability of radio channel of information transfer. Than the level of noise is higher, that the probability of error is more.

scholarly journals Noise immunity of receiving signals with amplitude and phase-shift keying in the presence of phase-shift keying interference

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
G.V. Kulikov ◽  
◽  
Khang Dang ◽  
Keyword(s):  
Phase Shift ◽  
Noise Immunity ◽  
Transmission Rate ◽  
Radio Channel ◽  
Signal Spectrum ◽  
Digital Television ◽  
Phase Shift Keying ◽  
Video Information ◽  
Useful Signal ◽  
Shift Keying

The development of television technologies and the need to transmit high-quality video information requires that modern digital television and broadcasting systems can transmit large amounts of information. The use of signals with multi-position amplitude and phase-shift keying 16-APSK and 32-APSK in DVB-S2 generation satellite television systems made it possible to transmit 30% more data in the same frequency bands compared to the previous DVB-S standard. The latest DVB-S2X digital satellite TV standard is an extension of the DVB-S2 standard and supports modulations of 64,128,256-APSK. It is known that increasing the positionality of signals reduces the noise immunity of their reception and the system as a whole. In addition, the presence of non-fluctuation interference in the radio channel that falls into the frequency band of the useful signal has a strong influence on noise immunity. The article uses statistical radio engineering methods to calculate the probability of a bit error when receiving M-APSK signals against the background of phase-shift keying interference at different parameters of the latter. It is shown that of phase-shift keying interference of even low intensity (µ < 0.3) falling into the main lobe of the signal spectrum significantly reduces the noise immunity of receiving 16-APSK and 32-APSK signals. High-intensity interference (µ ≥ 0.5) practically destroys reception. The influence of phase-shift keying interference decreases with an increase in its detuning relative to the carrier frequency of the useful signal and an increase in the relative transmission rate of the interference. A comparison of the reception quality when using M-PSK, M-QAM and M-APSK signals is carried out and it is shown that the noise immunity of receiving M-QAM and M-APSK against the background of phase-shift keying interference is approximately the same. M-PSK signals are significantly inferior to them in terms of reception noise immunity.

INSTRUMENTAL METHODS OF SHIPBOARD VHF RADIO COMMUNICATIONS QUALITY MEASURING

2021 ◽  
Author(s):  
М.Б. ПРОЦЕНКО ◽  
В.В. ГРОМОЗДИН ◽  
К.В. ИЕВЛЕВ ◽  
М.С. КОЗУБ
Keyword(s):  
Electromagnetic Field ◽  
Field Strength ◽  
Signal To Noise Ratio ◽  
Radio Channel ◽  
Signal To Noise ◽  
Radio Communications ◽  
Useful Signal ◽  
Electromagnetic Field Strength ◽  
Radio Equipment ◽  
Instrumental Methods

В работе рассмотрены такие характеристики судового ОВЧ радиоканала, как напряженность поля полезного сигнала и ЭДС полезного сигнала на входе радиоприемного устройства (РПУ),которые являются функциями от отношения сигнал/шум на выходе (входе)РПУ. Введено понятие фактической чувствительности РПУ. Определены количественные значения анализируемых характеристик применительно к типовому судовому радиооборудованию и шумовой обстановке вблизи судовой антенны. The article considers such characteristics of the shipboard VHF radio channel as the electromagnetic field strength of the useful signal and the EMF of the useful signal at the input of the receiver, which are functions of the signal-to-noise ratio at the output (input) of the receiver. The concept of the actual sensitivity of the receiver is introduced. The quantitative values of the analyzed characteristics are determined in relation to the typical ship radio equipment and the noise environment near the ship antenna.

Nested code sequences of Barker — Mersenne — Raghavarao

2019 ◽  
pp. 71-81
Author(s):  
M. B. Sergeev ◽  
V. A. Nenashev ◽  
A. M. Sergeev
Keyword(s):  
Data Transfer ◽  
Radio Channel ◽  
Main Peak ◽  
Synthesis Methods ◽  
Orthogonal Matrices ◽  
Useful Signal ◽  
New Codes ◽  
Increase In Accuracy ◽  
Application Fields ◽  
Barker Codes

Introduction: The problem of noise-free encoding for an open radio channel is of great importance for data transfer. The results presented in this paper are aimed at stimulating scientific interest in new codes and bases derived from quasi-orthogonal matrices, as a basis for the revision of signal processing algorithms.Purpose: Search for new code sequences as combinations of codes formed from the rows of Mersenne and Raghavarao quasi-orthogonal matrices, as well as complex and more efficient Barker — Mersenne — Raghavarao codes.Results: We studied nested code sequences derived from the rows of quasi-orthogonal cyclic matrices of Mersenne, Raghavarao and Hadamard, providing estimates for the characteristics of the autocorrelation function of nested Barker, Mersenne and Raghavarao codes, and their combinations: in particular, the ratio between the main peak and the maximum positive and negative “side lobes”. We have synthesized new codes, including nested ones, formed on the basis of quasi-orthogonal matrices with better characteristics than the known Barker codes and their nested constructions. The results are significant, as this research influences the establishment and development of methods for isolation, detection and processing of useful information. The results of the work have a long aftermath because new original code synthesis methods need to be studied, modified, generalized and expanded for new application fields.Practical relevance: The practical application of the obtained results guarantees an increase in accuracy of location systems, and detection of a useful signal in noisy background. In particular, these results can be used in radar systems with high distance resolution, when detecting physical objects, including hidden ones.

Study on the Performance of Chaotic Oscillator in Weak Signal Detection

2012 ◽  
Vol 263-266 ◽  
pp. 516-520
Author(s):  
Yan Mang Su ◽  
Zhen Bin Gao ◽  
Xiao Zhe Liu ◽  
Na Zheng
Keyword(s):  
Initial Phase ◽  
Signal To Noise Ratio ◽  
Sampling Frequency ◽  
Signal Frequency ◽  
Chaotic Oscillator ◽  
Reference Frequency ◽  
Weak Signal Detection ◽  
Accuracy Rate ◽  
Frequency Detection ◽  
Output Variance

For the frequency detection by using chaotic oscillator, in this paper, the results which are under the influence of the sampling frequency on the basis of theory that the output variance of the system will reach a maximum when the reference frequency equals to the signal frequency are analyzed. Experiments have indicated that the accuracy rate of the results will be improved and the signal to noise ratio (SNR) threshold will be reduced by increasing the sampling frequency to a certain degree. Besides, we have a further research on detecting the frequency of a signal with an initial phase based on the theory mentioned above, simulation experimental results have verified the output variance still has a drastic change when the reference frequency is equal to the signal frequency.

Analysis of neural networks efficiency when accounting for weight coefficients jitter, leading to reduction in output signal/noise ratio

2021 ◽  
Author(s):  
S.V. Zimina
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Artificial Neural Network ◽  
Output Signal ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Useful Signal ◽  
Artificial Neural ◽  
Noise Ratio ◽  
Weight Coefficients

Setting up artificial neural networks using iterative algorithms is accompanied by fluctuations in weight coefficients. When an artificial neural network solves the problem of allocating a useful signal against the background of interference, fluctuations in the weight vector lead to a deterioration of the useful signal allocated by the network and, in particular, losses in the output signal-to-noise ratio. The goal of the research is to perform a statistical analysis of an artificial neural network, that includes analysis of losses in the output signal-to-noise ratio associated with fluctuations in the weight coefficients of an artificial neural network. We considered artificial neural networks that are configured using discrete gradient, fast recurrent algorithms with restrictions, and the Hebb algorithm. It is shown that fluctuations lead to losses in the output signal/noise ratio, the level of which depends on the type of algorithm under consideration and the speed of setting up an artificial neural network. Taking into account the fluctuations of the weight vector in the analysis of the output signal-to-noise ratio allows us to correlate the permissible level of loss in the output signal-to-noise ratio and the speed of network configuration corresponding to this level when working with an artificial neural network.

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