Sidelobes Reduction Using Simple Two and Tri-Stages Non Linear Frequency Modulation (Nlfm)

Chan, Yee Kit; Chua, Ming Yam; Koo, Voon Chet

doi:10.2528/pier09073004

Cited by 50 publications

(39 citation statements)

References 10 publications

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“…Multi-wavelength fiber laser-based COSPEC has a good sensitivity (absorptions 10 −3 ) for the concentration measurement without any SNR enhancement techniques. In the future the manual adjustment of FBGs can be replaced with automatic adjustment with piezoelectric ceramics (PZT), and the results can be improved further if wavelength modulation spectroscopy (WMS) [25] or cavity enhancement technique (like a multi-pass cell) is utilized.…”

Section: Discussionmentioning

confidence: 99%

Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser

Wang¹,

Somesfalean²,

Mei³

et al. 2011

PIER

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Abstract-A correlation spectroscopy (COSPEC) based on a multiwavelength fiber laser is first proposed for the detection of gas concentration. The lasing wavelengths are selected to match several characteristic absorption peaks of the gas under test, and the gas concentration is easily measured by correlating it with the reference gas. The present method is immune from the instability of the light source and the influence of other gases. The concentration measurement of C 2 H 2 is demonstrated in the experiment in its nearinfrared dominant absorption region. The technique has prospects for simultaneous detection of multiple gases, and the measurement of mixed gases of C 2 H 2 and CO 2 is also analyzed.

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Section: Discussionmentioning

confidence: 99%

Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser

Wang¹,

Somesfalean²,

Mei³

et al. 2011

PIER

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“…In order to conserve LFM range resolution, a significant widening of the frequency range is necessary (about 1.86 times). Also, used as sidelobe reduction technique, Taylor spectrum window is more efficient than other tested PSD functions [3,10,12], (i.e., an average sidelobe decrease of 2 dB was achieved).…”

Section: Synthesis and Analysis Of The Nlfm Signal Using A Taylor Psdmentioning

confidence: 99%

“…According to (10), the idealized shape assigned to the normalized envelope of the signal autocorrelation function ρ id T (·) will be given by the equation (Fig. 3):…”

Section: Synthesis and Analysis Of The Nlfm Signal Using A Taylor Psdmentioning

confidence: 99%

“…However, all these processing methods can be generally divided into two major research directions, namely: a) design and synthesis of pseudo-NLFM (piecewise) waveforms which are in fact, signals with LFM predistortioned on short intervals into temporal domain or corrected into spectral domain [10,11]; b) design and synthesis of proper (i.e., as predefined shape of the energy/power spectral density (E/PSD) function) pure NLFM waveforms using for example, proper iterative methods [3,11], stationary phase principle, [12][13][14][15] or explicit functions cluster method [16] etc. In addition, the most part of the processing methods used to assure a consistent sidelobes reduction belonging to standard computational techniques [6][7][8][9][10][11][12][13][14][15][16], but some interesting aspects connected with AI paradigms are also discussed in literature [17].…”

Section: Introductionmentioning

confidence: 99%

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Sidelobes Reduction Using Synthesis of Some NLFM Laws

Vizitiu¹

2013

PIER B

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Abstract-It is well known that using proper signal compression techniques, the range resolution of the radar systems can be enhanced without having to increase the peak transmits power. Whereby the range resolution is inverse proportional with the frequency band of the scanning signals, in the last period of time, in radar systems literature a lot of suitable wideband signals were designed and analyzed as performance level. However, for the large majority of these signals, the compression filter response contains significant sidelobes which may cause difficulties in the target detection and range estimation process. Consequently, in the radar signal processing theory, the sidelobes reduction techniques using synthesis of some proper nonlinear FM (NLFM) laws represents a major scientific research direction. In order to assure the sidelobes suppression, the main objective of this paper is to present an adequate synthesis algorithm of some NLFM laws based on stationary phase principle. The achieved experimental results confirm a significant sidelobes reduction (i.e., more than −40 dB) without necessity to apply some weighting techniques. Finally, the analysis of the synthesized NLFM laws by ambiguity function tool was also discussed.

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“…The narrowband jamming signal source is composed of a narrowband VCO, a narrowband PA, a switch (SW), and an LFM. The chirp spread spectrum is obtained by modulating each narrowband VCO [5]. The output frequency band is selected by the switch.…”

Section: Introductionmentioning

confidence: 99%

20 MHz-3 GHz Programmable Chirp Spread Spectrum Generator for a Wideband Radio Jamming Application

Kim¹,

Ryu²,

Ha³

et al. 2014

Journal of Electrical Engineering and Technology

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-In this paper, an agile programmable chirp spread spectrum generator for wideband frequency-jamming applications from 20 MHz to 3 GHz is proposed. A frequency-mixing architecture using two voltage-controlled oscillators is used to achieve a wideband operating frequency range, and the direct digital synthesizer (DDS)-based chirping method with a two-point modulation technique is employed to provide a programmable and consistent chirp bandwidth. The proposed signal generator provides the various programmable FM signals from 20 MHz to 3 GHz with a modulation bandwidth from 0 to 400 MHz. The prototype successfully demonstrates arbitrary sequential jamming operation with a fast band-to-band hopping time of < 10 μsec.

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Sidelobes Reduction Using Simple Two and Tri-Stages Non Linear Frequency Modulation (Nlfm)

Cited by 50 publications

References 10 publications

Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser

Detection of Gas Concentration by Correlation Spectroscopy Using a Multi-Wavelength Fiber Laser

Sidelobes Reduction Using Synthesis of Some NLFM Laws

20 MHz-3 GHz Programmable Chirp Spread Spectrum Generator for a Wideband Radio Jamming Application

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