Random Signals

Mohanty, Nirode

doi:10.1007/978-94-011-7041-3_1

Cited by 2 publications

(2 citation statements)

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“…As is known, the cross-correlation function can be used to analyze the degree of similarity of two signals. To mathematically compare the two techniques, we introduce the correlation coefficient

, which is defined by the normalized value of the cross-correlation function at zero time as follows [ 26 ],

where

is the true RHS quadrature component and

is the reconstructed RHS quadrature component. Obviously, a correlation coefficient that is more close to 1 represents a better RHS reconstruction performance.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging

Liu

Wang

et al. 2016

Sensors

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Forward scatter radar (FSR), as a specially configured bistatic radar, is provided with the capabilities of target recognition and classification by the Shadow Inverse Synthetic Aperture Radar (SISAR) imaging technology. This paper mainly discusses the reconstruction of radio holographic signal (RHS), which is an important procedure in the signal processing of FSR SISAR imaging. Based on the analysis of signal characteristics, the method for RHS reconstruction is improved in two parts: the segmental Hilbert transformation and the reconstruction of mainlobe RHS. In addition, a quantitative analysis of the method’s applicability is presented by distinguishing between the near field and far field in forward scattering. Simulation results validated the method’s advantages in improving the accuracy of RHS reconstruction and imaging.

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, which is defined by the normalized value of the cross-correlation function at zero time as follows [ 26 ],

where

is the true RHS quadrature component and

is the reconstructed RHS quadrature component. Obviously, a correlation coefficient that is more close to 1 represents a better RHS reconstruction performance.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging

Liu

Wang

et al. 2016

Sensors

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“…Based on the principle of lock-in amplifier (Alexander, 2009; Brisges 1988; Brown, 1983; Connor, 1982; Fish, 1993; Howard, 2002; Jiri, 2000; Mcdonough and Whalen, 1995; Mohanty, 1986; Ott, 1988; Van, 1987; Wilmshurst, 1985) and THz-TDS optical path, we propose the general design of the data acquisition system as below. Input is the signal to be measured through terahertz signal optical chopper after chopping, the reference signal output from chopper is served as the reference signal.…”

Section: Design Of the Systemmentioning

confidence: 99%

Development of the data acquisition system for terahertz spectrometer

Hu¹,

Shen²,

Han³

et al. 2017

Transactions of the Institute of Measurement and Control

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In most Terahertz time-domain spectrometer (THz-TDS) experiments, the lock-in amplifier works with trans-impedance pre-amplifier to amplitude the terahertz pulse accepted from detector. This paper discusses the development of data acquisition system for the transmission THz-TDS. In this system, the cross-correlation software algorithm in SR830 lock-in amplifier from Stanford Research Systems, that is usually used in THz-TDS, has been replaced by parallel hardware algorithm of Field Programmable Gate Array (FPGA) chip with the parallel processing ability. This chip has a faster processing speed and higher accuracy than others. A 24 bit Delta-Sigma Analog Digital (AD) was used in place of the 16 bit successive approximation ADC of SR830. The new AD convertor can reduce the complexity of trans-impedance pre-amplifier circuit and replace the SR555 current amplifiers that designed to work with SRS lock-in amplifiers. Besides trans-impedance pre-amplifier circuit, all function circuits, such as low-pass digital filter, phase-locked loop, Direct Digital Synthesis (DDS) reference source and the core algorithms, are integrated in a FPGA chip, which make the new designed lock-in amplifier with a small volume reduce a dozen times SR830 size.

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Random Signals

Cited by 2 publications

References 0 publications

Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging

Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging

Development of the data acquisition system for terahertz spectrometer

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