Acousto-optical semiconductor laser power spectrum analyzer of RF signals with expanded dynamic range

1996 ◽  
Author(s):  
Anatolii I. Averyanov ◽  
Alexander F. Buchenskii ◽  
Emmanuil I. Krupitskii ◽  
Sergey V. Morozov ◽  
Vladimir Y. Pelevin ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Semiconductor Laser ◽  
Laser Power ◽  
Dynamic Range ◽  
Spectrum Analyzer ◽  
Rf Signals

scholarly journals Optical spectroanalyzer with extended dynamic range for pharmacokinetic investigations of photosensitizers in biotissue

2019 ◽  
Vol 8 (1) ◽  
pp. 46-51 ◽  
Author(s):  
G. A. Meerovich ◽  
E. V. Akhlyustina ◽  
T. A. Savelieva ◽  
K. G. Linkov ◽  
V. B. Loschenov
Keyword(s):  
Dynamic Range ◽  
Spectrum Analyzer ◽  
Pharmacokinetic Studies ◽  
Fluorescent Properties ◽  
Accumulation Time ◽  
Fluorescent Method ◽  
Calibration Samples ◽  
Hardware Circuit ◽  
Improved Accuracy ◽  
Extended Dynamic

Currently, the most promising method for the study of pharmacokinetics of drugs with fluorescent properties is the spectral-fluorescent method. In this article, we propose an algorithm for expanding the dynamic range of the spectrum analyzer by automatically monitoring the maximum spectral density in the recorded fluorescence spectrum and automatically controlled changes in the accumulation time depending on this value, followed by compensation of the output signal with regard to this change, as well as hardware circuit solutions that allow this algorithm.Testing of LESA-01-"Biospeс" spectrum analyzer, upgraded using the proposed approach, was carried out on photosensitizer dispersions based on tetra-3-phenylthiophthalocyanine hydroxyaluminium of various concentrations (from 0.01 mg/l to 50 mg/l), approximately corresponding to the concentrations realized in the process of studying pharmacokinetics in calibration samples and tissues of experimental animals.The proposed solutions that implement the algorithm for recording fluorescence spectra with automatic change of accumulation time depending on the signal level, ensured a significant expansion of the dynamic range of the spectrum analyzer (up to 3.5 orders of magnitude) and improved accuracy in pharmacokinetic studies.

scholarly journals Extracting the external-cavity key of a chaotic semiconductor laser with double optical feedback by spectrum analyzer

2012 ◽  
Vol 61 (3) ◽  
pp. 034211
Author(s):  
Liang Jun-Sheng ◽  
Wu Yuan ◽  
Wang An-Bang ◽  
Wang Yun-Cai
Keyword(s):  
Semiconductor Laser ◽  
Optical Feedback ◽  
External Cavity ◽  
Spectrum Analyzer

A photonic transmission link with enhanced dynamic range by incorporating phase shifters in dual drive dual parallel Mach–Zehnder modulator

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarika Singh ◽  
Sandeep K. Arya ◽  
Shelly Singla ◽  
Pulkit Berwal
Keyword(s):  
Dynamic Range ◽  
Control Method ◽  
Phase Shifters ◽  
Optical Modulator ◽  
Rf Signals ◽  
Single Sideband Modulation ◽  
Spurious Free Dynamic Range ◽  
Optical Single Sideband ◽  
Mach Zehnder Modulator ◽  
Free Dynamic

Abstract A linearization scheme is proposed for microwave photonic link to enlarge spurious free dynamic range using a dual-electrode dual parallel Mach–Zehnder modulator (MZM). This scheme employs phase control method to improve performance of the link by adjusting phase of radio frequency (RF) signals and bias voltages of optical modulator. Optical single sideband modulation is achieved through sub-modulators of dual parallel MZM which increases efficiency of the link. The simulated results show that third order intermodulation distortion is suppressed by 28 dB when the input RF signals are 9.1 and 9.5 GHz and noise floor is at −161 dBm/Hz. The spurious free dynamic range is also improved by 12.6 dB.

scholarly journals Interferometric observations of the small-scale structure of Galactic neutral hydrogen

1985 ◽  
Vol 106 ◽  
pp. 321-322
Author(s):  
J. Crovisier ◽  
J. M. Dickey
Keyword(s):  
Power Spectrum ◽  
Dynamic Range ◽  
Neutral Hydrogen ◽  
Scale Structure ◽  
Small Scale ◽  
Turbulence Spectrum ◽  
Small Scale Structure ◽  
Image Position ◽  
Spatial Power Spectrum

The small-scale structure of galactic neutral hydrogen may be statistically described by the spatial power spectrum of the 21-cm line. This latter may be readily observed by interferometer arrays since it is the squared modulus of the visibility function. We have observed the , region with the Westerbork Synthesis Radio Telescope (Crovisier and Dickey, 1983). Brightness fluctuations of the 21-cm line were detected in this region on scales as small as 1.7 arcmin (corresponding to less than 5 pc). The Westerbork observations, combined with single-dish observations made at Nançay and Arecibo, allow determination of the spatial power spectrum over a dynamic range of about 106 in intensity. The spectrum follows roughly a power law with indices ~ −3 to −2. An interpretation in terms of the turbulence spectrum is proposed by Dickey (1985).

Time-integrating optical raster spectrum analyzer using semiconductor laser as input modulator

1991 ◽  
Author(s):  
Alexander Larkin ◽  
Alexander K. Matveev ◽  
Yury A. Mironov
Keyword(s):  
Semiconductor Laser ◽  
Spectrum Analyzer

The Practical Significance of Two-Dimensional Deconvolution in Echography

1987 ◽  
Vol 9 (2) ◽  
pp. 106-116 ◽  
Author(s):  
T.J.M. Jeurens ◽  
J.C. Somer ◽  
F.A.M. Smeets ◽  
A.P.G. Hoeks
Keyword(s):  
Dynamic Range ◽  
Power Level ◽  
Homogeneous Medium ◽  
Practical Significance ◽  
Noise Power ◽  
Two Dimensional ◽  
Inverse Filtering ◽  
Inverse Filter ◽  
Ultrasonic Beam ◽  
Rf Signals

This paper evaluates deconvolution (inverse filtering) as applied to ultrasonic imaging systems, and discusses the obstacles which are encountered employing the technique in practice. A minicomputer is used to generate artifical echo signals, simulating rf signals resulting from a set of point reflectors in a homogeneous medium, as recorded by an electronically focused group-steered linear array scanner. Two-dimensional deconvolution in combination with a Wiener noise reduction filter (i.e., a Wiener-Inverse filter) is applied to these simulated rf signals, which were contaminated with white noise. The efficacy of the Wiener-Inverse filter is defined in terms of its ability to resolve two point reflectors with a lateral spacing equal to the local −6 dB width of the ultrasonic beam. In favorable circumstances, the targets are resolved at signal-to-noise ratios (SNR) better than 20 dB, where SNR is defined as the maximum signal power divided by the average noise power level. Nonlinear effects due to quantization or signal clipping are investigated. In order to improve the resolution of an rf signal with a dynamic range of 40 dB, the input signal should be digitized at a minimum of 12 bits. The problem of signal clipping can be circumvented by oversampling. The two-dimensional Wiener-Inverse filter is defined in terms of both temporal and spatial properties of the insonification. Effects of wave diffraction give rise to a depth-dependent ultrasonic beam. As a result of a misfit of the Wiener-Inverse filter and the local properties of the ultrasonic beam, erroneous noisy texture arises in the image. Adaptation of the Wiener-Inverse filter with respect to the beam properties gives acceptable results, at the expense of a rather large computational effort.

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