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Wyświetlanie 1-8 z 8
Tytuł:
Structure Optimization of Phase-Coded Sounding Signals
Autorzy:
Szczegielniak, D.
Milewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1537555.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
84.40.Xb
Opis:
Pulse compression with a small sidelobe level is one of challenges in designing of modern radar, sonar or ultrasound imaging systems. It may be performed by means of matched filter, that is by correlating the received sounding signal with a stored replica of the transmitted signal. The advantage of the pulse compression method is the increase of the average transmission power while retaining the range resolution corresponding to a short pulse. Phase coding is one of the early techniques for pulse compression of radar signals. Polyphase sequences, which have low sidelobe levels, ensure an easily detectable peak in the output of a matched filter, in other words an easy detection of a received sounding signal. In this paper, an evolutionary algorithm combined with a local optimizer is used to search for polyphase codes with a small sidelobe level of an aperiodic autocorrelation function. The evolutionary algorithm is based on a floating-point representation and the Gaussian mutation is used to produce offspring for the next generation. The self-adaptation mechanism is used to control the mutation operator during the evolutionary process. This research demonstrates that optimization methods can effectively find polyphase sequences with low autocorrelation and seems to be very promising for the future research in area of computer optimization for polyphase codes synthesis.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 164-167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Matched Filtration of LFM Signals with Non-Zero Initial Frequency
Autorzy:
Leszczynski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1399382.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Xb
84.40.Ua
Opis:
This paper presents the results of the research considering the influence of the initial frequency on linear frequency modulation signal compression. The signal compression has been performed using the digital matched filtration in the time domain. The ratio of peak to side lobe ratio with the width of the main lobe equaling one sampling period is the measure of the quality of compression. In general, a lower value of peak to side lobe ratio is obtained for linear frequency modulation signals with a non-zero initial frequency than with a zero initial frequency. The peak to side lobe ratio is systematically decreasing with the increase of the initial frequency f_1. The existing methods of band signals sampling, where the spectrum of the signals is transferred by means of the carrier signal $f_0$ of a significantly higher frequency than the band B ($f_0$ ≫ B) may be effectively used for sampling signals considered in this study, which do not have a carrier. As a result, for the linear frequency modulation signals with a non-zero initial frequency $f_1$ = nB and a final frequency $f_2$ = (n + 1) B, n = 1, 2, ..., the same peak to side lobe ratio values will be obtained as for linear frequency modulation signals with a zero initial frequency and the identical band and time duration. The results of this research could be implemented in sonar and radiolocation techniques and medicine.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 494-497
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Radar Ambiguity Function Application for the Frequency Modulated Signals Designing
Autorzy:
Kawalec, A.
Ziołkowski, C.
Leśnik, C.
Pietrasinski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807731.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
84.40.Xb
Opis:
The optimization of the transmitted signal time-frequency structure is the very important part of the radar system design from the point of view of the radar system effectiveness. In this meaning the radar ambiguity function is the basic tool used for the radar system features testing. The synthesis procedure of the signal with simultaneous amplitude and phase manipulation is presented in the paper. The procedure is based on the Zak transform that is connected with the radar ambiguity function. The Legendre polynomials were applied in the procedure mentioned above. The results of the simulation tests are presented as examples of the consideration main effects.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 335-339
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Frequency Modulated Signal Design
Autorzy:
Leśnik, C.
Powiązania:
https://bibliotekanauki.pl/articles/1807736.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
84.40.Xb
Opis:
The signal time-frequency structure designing is the important problem of radar system solution optimisation. The radar ambiguity function is the very useful signal characteristic that enables to know the signal potential possibilities. The effective numerical methods of the radar ambiguity function calculation give possibility for synthesis of the radar signal having expected features. The synthesis method concerning the nonlinear frequency modulation radar signal is presented in the paper. For the radar ambiguity function calculation the Zak transform is used in the method. The nonlinear frequency modulation signal model was described in which application limitations were taken into account. Examples of simulation research results are presented as a comment of the considerations.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 351-354
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure Optimization of Coded Polyphase Signals with the Enhanced Tolerance to the Doppler Frequency Shift
Autorzy:
Szczegielniak, D.
Milewski, A.
Szczegielniak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1401917.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
84.40.Xb
Opis:
The aim of this research was to verify if It is possible to solve the synthesis problem of polyphase codes efficiently with an acceptable quality in the context of radar applications - with the greatest possible effectiveness of the recognition of such signals in the presence of the noise and occurrence of the Doppler effect. The received results confirmed that the implemented optimization algorithm can search polyphase sequences successfully with a low level of sidelobes and an enhanced tolerance to the Doppler effect. Applying optimization methods allows to form ambiguity function in a measure in the assumed optimization range which seems to be encouraging for future examinations in the field of the computer optimization for the coded radar signals synthesis.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 452-455
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of a Weighting Function for NLFM Radar Signal Designing
Autorzy:
Leśnik, C.
Kawalec, A.
Powiązania:
https://bibliotekanauki.pl/articles/1811542.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
84.40.Xb
Opis:
Modification of the weighting raised cosine with a power n function by time convolution with auxiliary changeable time duration uniform rectangular window is presented in this paper. The analytical form of the modified weighting raised cosine function for fixed power in frequency domain was derived. Proposed method was applied to fine tuning of properties of the nonlinear frequency modulation of radar signals. Synthesis of nonlinear frequency modulation radar signals problem was solved using the well-known principle of stationary phase. The selected testing results are shown and some final conclusions are formulated.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-143-A-149
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antenna Beam Broadening in Multifunction Phased Array Radar
Autorzy:
Fatemi Mofrad, R.
Sadeghzadeh, R.
Powiązania:
https://bibliotekanauki.pl/articles/1505195.pdf
Data publikacji:
2011-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ba
84.40.Xb
84.40.Ua
Opis:
A phased array antenna is designed for multifunction phased array radar simulation test bed. Effect of element pattern, mutual coupling between elements, phase quantization, amplitude and phase error and elements failure rates on array pattern are discussed. Target angle measurement and side lobe cancelling, in order to reduce jamming power through side lobes, is illustrated in this antenna. Also antenna beam width is broadened with different methods and compared with narrow beam characteristics. It is shown that, for special broadening factors, beam broadening may lead to a better coverage and power efficiency relative to narrow beam antenna.
Źródło:
Acta Physica Polonica A; 2011, 119, 4; 461-466
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Radar with Microwave Correlation Receiver
Autorzy:
Susek, W.
Stec, B.
Rećko, Cz.
Powiązania:
https://bibliotekanauki.pl/articles/1505215.pdf
Data publikacji:
2011-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.Hm
41.90.+e
84.40.Ua
84.40.Xb
84.40.Dc
Opis:
The idea of microwave quadrature correlation as well as the block diagram of the microwave broadband correlation receiver and principle of quadrature correlation detection of noise signals using an analog microwave correlator are presented in the paper. Measurement results for the correlation function of noise signals are shown and application of such solution in the noise radar for precise determination of distance changes and velocity of these changes is also presented. Results for short range noise radar operation are presented both for static and moving. Experimental results using 2.6-3.6 GHz noise like waveform for the signal from a breathing human is presented. Conclusions and future plans for the use of presented detection technique in broad-band noise radars close the paper.
Źródło:
Acta Physica Polonica A; 2011, 119, 4; 483-487
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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