Analysis of the operation of adaptive antenna arrays of communication systems maximizing the output signal-to-noise ratio

1994 ◽  
Vol 37 (3) ◽  
pp. 207-213
Author(s):  
A. M. Silaev
Keyword(s):  
Antenna Arrays ◽  
Output Signal ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Adaptive Antenna ◽  
Signal To Noise ◽  
Adaptive Antenna Arrays ◽  
Noise Ratio

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.

scholarly journals NOISE STABILITY OF SIGNAL RECEPTION ALGORITHMS WITH MULTIPULSE PULSE-POSITION MODULATION

2018 ◽  
Vol 42 (1) ◽  
pp. 167-174 ◽  
Author(s):  
V. I. Parfenov ◽  
D. Y. Golovanov
Keyword(s):  
Communication Systems ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Estimation Accuracy ◽  
Pulse Position Modulation ◽  
Signal To Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Ratio

An algorithm for estimating time positions and amplitudes of a periodic pulse sequence from a small number of samples was proposed. The number of these samples was determined only by the number of pulses. The performance of this algorithm was considered on the assumption that the spectrum of the original signal is limited with an ideal low-pass filter or the Nyquist filter, and conditions for the conversion from one filter to the other were determined. The efficiency of the proposed algorithm was investigated through analyzing in which way the dispersion of estimates of time positions and amplitudes depends on the signal-to-noise ratio and on the number of pulses in the sequence. It was shown that, from this point of view, the efficiency of the algorithm decreases with increasing number of sequence pulses. Besides, the efficiency of the proposed algorithm decreases with decreasing signal-to-noise ratio.It was found that, unlike the classical maximum likelihood algorithm, the proposed algorithm does not require a search for the maximum of a multivariable function, meanwhile characteristics of the estimates are practically the same for both these methods. Also, it was shown that the estimation accuracy of the proposed algorithm can be increased by an insignificant increase in the number of signal samples.The results obtained may be used in the practical design of laser communication systems, in which the multipulse pulse-position modulation is used for message transmission. 

scholarly journals Calculations of Signal to Noise Ratio (SNR) for Free Space Optical Communication Systems

2008 ◽  
Vol 5 (1) ◽  
pp. 95-100
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Full Duplex ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Communication Systems ◽  
Space Optical Communication ◽  
Noise Ratio

In this paper, we calculate and measure the SNR theoretically and experimental for digital full duplex optical communication systems for different ranges in free space, the system consists of transmitter and receiver in each side. The semiconductor laser (pointer) was used as a carrier wave in free space with the specification is 5mW power and 650nm wavelength. The type of optical detector was used a PIN with area 1mm2 and responsively 0.4A/W for this wavelength. The results show a high quality optical communication system for different range from (300-1300)m with different bit rat (60-140)kbit/sec is achieved with best values of the signal to noise ratio (SNR).

scholarly journals Joint use of frequency-time division and antinoise coding in radio communication systems with FHSS

2021 ◽  
Vol 9 (4) ◽  
pp. 77-84
Author(s):  
A. A. Paramonov ◽  
Van Zung Hoang
Keyword(s):  
Data Transmission ◽  
Communication Systems ◽  
Error Probability ◽  
Noise Immunity ◽  
Signal To Noise Ratio ◽  
Frequency Division ◽  
Radio Communication ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Time Division

In the context of continuous improvement of radio prospecting and active radio jamming technics along with introduction of automated active countermeasures systems (ACS), the frequency-hopping spread spectrum (FHSS) radio communication systems (RCS) are widely used in order to improve reliability and noise immunity of data transmission. The noise immunity of the RCS affected by unintentional or deliberate interference can be significantly perfected by the combined use of frequency-time division and antinoise coding. This paper explores the case when the interference created by an ACS system with a limited transmitter power covers a part of the RCS frequency range. The receiver gets input mix of the wanted signal, the receiver noise, and probably a deliberate interference also considered as a noise. The article analyzes the noise immunity of signals reception with FHSS in the low-speed radio systems with joint use of frequency-time division of information subsymbols and noise combating codes when the deliberate interference destructively impacts a part of the RCS working band. Dependence of the bit error probability on the signal-to-noise ratio is calculated for the joint use of frequency division of information subsymbols and noise combating codes. It is shown that due to effective use of the frequency-energy resource of a radio line, considering the use of correction codes, a quite high noise immunity of RCS under the influence of deliberate interference can be assured. The indicated dependences of the error probability on the signal-to-noise ratio confirm that the reliability of data transmission can be significantly increased by the proper combination of signal spectrum spreading, applying of correction codes, and frequency division of subsymbols followed by their weight processing.

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