An iterative approach for minimax design of multidimensional quadrature mirror filters

Low probability of intercept radar signals, which are often problematic to detect and characterize, have as their goal ‘to see and not be seen’. Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing these low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency hopping radar signals through utilization and direct comparison of the Spectrogram versus the Scalogram. Two different frequency hopping low probability of intercept radar signals were analyzed(4-component and 8-component). The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, and timefrequency localization. Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Scalogram produced more accurate characterization metrics than the Spectrogram. An improvement in performance may well translate into saved equipment and lives.

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Low Probability of Intercept Frequency Hopping Signal Characterization Comparison using the Spectrogram and the Scalogram

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency modulated continuous wave radar signals through utilization and direct comparison of the Spectrogram versus the Scalogram. Two different triangular modulated frequency modulated continuous wave signals were analyzed. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Spectrogram produced more accurate characterization metrics than the Scalogram. An improvement in performance may well translate into saved equipment and lives. GJRE-F Classification: FOR Code: 090609 LowProbabilityofInterceptTriangularModulatedFrequencyModulatedContinuousWaveSignalCharacterizationComparisonusingtheSpectrogramandtheScalogram Strictly as per the compliance and regulations of : Global Journal of Researches in Engineering: F Electrical and Electronics Engineering Volume 17 Issue 2 Version 1.0 Year 2017 Type: Double Blind Peer Reviewed International Research Journal Publisher: Global Journals Inc. (USA) Online ISSN: 2249-4596 & Print ISSN: 0975-5861

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Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison using the Spectrogram and the Scalogram

Son yıllarda hızlı sayısal süzgeçler ve süzgeç bankalarında önemli gelişmeler olmuştur. Çoklu hıza sahip süzgeç bankalarının bir uygulaması olarak bilinen QMF (Çeyrek Ayna Süzgeç-Quadrature Mirror Filter) bankası alt bant kodlama, görüntü sıkıştırma, kelime kodlama, biyomedikal sinyal işleme ve haberleşme sistemlerinde yaygın olarak kullanılmaktadır. Bu çalışmada; QMF bankası tasarımında istenilmeyen salınımları ortadan kaldırmak için Kaiser ve Hamming pencerelerinin kaskat bağlanması ile elde edilen pencere fonksiyonu kullanılarak tasarlanan prototip FIR (Finite Impulse Response-Sonlu dürtü tepkili) süzgeçle QMF bankası tasarımı gerçekleştirilmiştir. Farklı pencere fonksiyonları ile tasarlanan süzgeçlerde süzgecin derecesinin performansı nasıl değiştirdiği incelenmiş ve sonuçta daha yüksek durdurma bandı zayıflaması sergileyen Kaiser-Hamming penceresinin QMF bankası tasarımında kullanılabileceği sonucuna varılmıştır. In recent years, significant improvements have been in fast digital filters and filter banks. QMF (Quadrature Mirror Filter) bank, known as an application of multi-speed filter banks are widely used sub-band coding, image compression, word coding, biomedical signal processing and communication systems. In this study; QMF bank design is realized via a windowing method with prototype FIR (Finite Impulse Response) filter design and based on cascade bounded Kaiser and Hamming windows for eliminating undesired oscillations in QMF bank design. It has been investigated how the performance changed of the filter degree in designing filter with different window functions and at the result it is shown that Kaiser-Hamming window with lower stopband attenuation could be used in QMF bank design.

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Investigation of the performance of the Kaiser-Hamming window in design of QMF bank

In the digital filter bank context, many design methods have been proposed. Most of them are for 2-band QMF FIR filter banks. The paper considers the design of (QMF) quadrature mirror filter banks using the iterative method proposed by Chang-Kann Chen and Ju-Hong Lee (1992). Simulations show that the Chen and Lee method needs much iteration. It was examined and improved by using certain modifications based on the weighted least squares (WLS) updating scheme proposed by S. Sunder et al. (1994) to design two channel QMF filter banks. As the current weighting function is adjusted from iteration to iteration, QMF bank design with equiripple reconstruction error and stopband error can be achieved. Computer simulation shows that the proposed approach produced better results than those reported previously by author Chen and Lee. The paper concludes with design examples that illustrate the effectiveness of the approach on the efficiency and performance. Furthermore, the proposed approach requires less iterations compared with existing methods and leads to filter bank design with improved performance. The resultant filter banks are efficient in terms of computational requirements.

M.J. Nigam

Papers

On the design of 2-band FIR QMF filter banks using WLS technique