The Experts below are selected from a list of 34731 Experts worldwide ranked by ideXlab platform
B Boashash - One of the best experts on this subject based on the ideXlab platform.
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multi component Instantaneous Frequency estimation using locally adaptive directional time Frequency distributions
International Journal of Adaptive Control and Signal Processing, 2016Co-Authors: Nabeel Ali Khan, B BoashashAbstract:This paper presents a locally adaptive time-Frequency t,f method for estimating the Instantaneous Frequency IF of multi-component signals. A high-resolution adaptive directional time-Frequency distribution ADTFD is defined by locally adapting the direction of its smoothing kernel at each t,f point based on the direction of the energy distribution in the t,f domain. The IF of signal components is then estimated from the ADTFD using an image processing algorithm. Using the mean square error between the original IF and estimated IF as a performance criterion, experimental results indicate that the ADTFD gives better IF estimation performance compared with other TFDs for a multi-component signal. For example, for signal-to-noise ratio of 12dB, the IF estimate obtained using the ADTFD achieves a mean square error of -42dB for a weak signal component, which is an improvement of -12dB compared with other TFDs. Copyright © 2015John Wiley & Sons, Ltd.
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a cross terms geometry based method for components Instantaneous Frequency estimation using the cross wigner ville distribution
Information Sciences Signal Processing and their Applications, 2012Co-Authors: Damir Malnar, Victor Sucic, B BoashashAbstract:A novel method for the signal components Instantaneous Frequency (IF) estimation based on the CrossWigner-Ville distribution (XWVD) is presented. The cross-terms in the XWVD are deliberately formed between the analyzed signal and a reference signal. The proposed method yields a scaled and time shifted image that closely resembles the Instantaneous Frequency laws of the components present in the signal. As the interferences location follow geometrical rules, and by using a reference signal well localized in time and Frequency, the time-Frequency coordinates of the analyzed signal components IF can be calculated by an automatic procedure described below. The performance of the method is tested on both synthetic and real-life signals, showing improvements over another recently proposed components extraction method.
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mobile unit velocity estimation based on the Instantaneous Frequency of the received signal
IEEE Transactions on Vehicular Technology, 2004Co-Authors: Ghasem Azemi, Bouchra Senadji, B BoashashAbstract:This paper presents a new mobile station velocity estimator based on the first moment of the Instantaneous Frequency (IF) of the received signal. The effects of shadowing, additive noise, and scattering distribution on the proposed velocity estimator are analyzed. We show that, unlike velocity estimators based on the envelope and quadrature components of the received signal, the proposed estimator is robust to shadowing. We also prove that the performance of the IF-based estimator is only mildly affected by the presence of additive noise. Finally, by using simulations we show that the performance of the proposed IF-based estimator is superior to that of existing velocity estimators.
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mobile unit velocity estimation in microcellular systems using the zcr of the Instantaneous Frequency of the received signal
Information Sciences Signal Processing and their Applications, 2003Co-Authors: Ghasem Azemi, Bouchra Senadji, B BoashashAbstract:This paper presents a new estimator for the velocity of a mobile station in microcellular systems. The proposed estimator is based on the zero-crossing rate of the Instantaneous Frequency of the received signal. The effects of additive noise, scattering distribution, and shadowing on the proposed velocity estimator are analyzed. The IF-based velocity estimator outperforms the conventional estimators in the presence of shadowing.
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use of the cross wigner ville distribution for estimation of Instantaneous Frequency
IEEE Transactions on Signal Processing, 1993Co-Authors: B Boashash, Peter OsheaAbstract:An iterative Instantaneous Frequency (IF) estimation scheme is presented in which successive IF estimates are obtained from the peak of the cross Wigner-Ville distribution (XWVD), using a reference signal synthesized from an initial IF estimate. Theoretical and practical aspects of performance are discussed, and the performance is compared with that of other methods. >
Arnan Mitchell - One of the best experts on this subject based on the ideXlab platform.
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amplitude independent photonic Instantaneous Frequency measurement with improved sensitivity
IEEE Photonics Journal, 2012Co-Authors: Niusha Sarkhosh, Hossein Emami, Arnan MitchellAbstract:A technique for improving the sensitivity of a class of broadband RF photonic Instantaneous Frequency measurement (IFM) systems is proposed and practically demonstrated. The technique utilizes lock-in amplification to isolate the desired signal from background noise. The demonstration is conducted on a dual orthogonal measurement IFM system utilizing multiple wavelengths and a transversal Hilbert transform achieving independent amplitude and Frequency measurements over a multioctave bandwidth with a sensitivity of $-$ 37 dBm. This performance is comparable with traditional electronic IFM receivers. The successful application of this lock-in approach to this multichannel photonic system illustrates its flexibility and indicates that it should be applicable to even more sophisticated systems.
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amplitude independent rf Instantaneous Frequency measurement system using photonic hilbert transform
Optics Express, 2008Co-Authors: Hossein Emami, Lam Anh Bui, Niusha Sarkhosh, Arnan MitchellAbstract:A photonic Instantaneous Frequency measurement system capable of measuring both RF Frequency and power simultaneously, is conceived and practically demonstrated. This system employs an RF photonic Hilbert transformer together with low-cost, low-Frequency photo-detectors to obtain two orthogonal DC measurements. This system exhibits a Frequency range of 1-10 GHz. Wider Frequency range can be achieved through integration.
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reduced cost photonic Instantaneous Frequency measurement system
IEEE Photonics Technology Letters, 2008Co-Authors: N Sarkhosh, Hossein Emami, Lam Anh Bui, Arnan MitchellAbstract:A wideband photonic Instantaneous Frequency measurement system is proposed and practically demonstrated. This system employs only a low-Frequency inexpensive photodetector and thus the system cost is reduced.
Hossein Emami - One of the best experts on this subject based on the ideXlab platform.
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microwave photonics Instantaneous Frequency measurement receiver based on a sagnac loop
Optics Letters, 2018Co-Authors: Hossein Emami, Mohammad Reza Hajihashemi, Sayed Ehsan Alavi, Abu Sahmah Mohd SupaatAbstract:A microwave photonics Instantaneous Frequency measurement receiver was conceived and practically demonstrated. The system is based on phase modulation inside a Sagnac loop and therefore needs no bias voltage, resulting in no DC bias drifts. The system provides a DC output whose amplitude is a function of input signal Frequency, and thus no high-Frequency photo-detector is required. Furthermore, the system exhibits a very good sensitivity without the aid of any sort of electrical noise cancellation techniques, such as lock-in amplification. This makes the system response faster, which would be another benefit for electronic warfare applications. Less than 6% measurement error was achieved over a 0.01–40 GHz Frequency range for −30 dBm RF level. Also, a 10% error was achieved at −51 dBm RF power level.
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amplitude independent photonic Instantaneous Frequency measurement with improved sensitivity
IEEE Photonics Journal, 2012Co-Authors: Niusha Sarkhosh, Hossein Emami, Arnan MitchellAbstract:A technique for improving the sensitivity of a class of broadband RF photonic Instantaneous Frequency measurement (IFM) systems is proposed and practically demonstrated. The technique utilizes lock-in amplification to isolate the desired signal from background noise. The demonstration is conducted on a dual orthogonal measurement IFM system utilizing multiple wavelengths and a transversal Hilbert transform achieving independent amplitude and Frequency measurements over a multioctave bandwidth with a sensitivity of $-$ 37 dBm. This performance is comparable with traditional electronic IFM receivers. The successful application of this lock-in approach to this multichannel photonic system illustrates its flexibility and indicates that it should be applicable to even more sophisticated systems.
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amplitude independent rf Instantaneous Frequency measurement system using photonic hilbert transform
Optics Express, 2008Co-Authors: Hossein Emami, Lam Anh Bui, Niusha Sarkhosh, Arnan MitchellAbstract:A photonic Instantaneous Frequency measurement system capable of measuring both RF Frequency and power simultaneously, is conceived and practically demonstrated. This system employs an RF photonic Hilbert transformer together with low-cost, low-Frequency photo-detectors to obtain two orthogonal DC measurements. This system exhibits a Frequency range of 1-10 GHz. Wider Frequency range can be achieved through integration.
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reduced cost photonic Instantaneous Frequency measurement system
IEEE Photonics Technology Letters, 2008Co-Authors: N Sarkhosh, Hossein Emami, Lam Anh Bui, Arnan MitchellAbstract:A wideband photonic Instantaneous Frequency measurement system is proposed and practically demonstrated. This system employs only a low-Frequency inexpensive photodetector and thus the system cost is reduced.
Vladimir Katkovnik - One of the best experts on this subject based on the ideXlab platform.
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minimax lower bounds for nonparametric estimation of the Instantaneous Frequency and time varying amplitude of a harmonic signal
Signal Processing, 2000Co-Authors: Vladimir KatkovnikAbstract:Abstract Estimation of the Instantaneous Frequency- and time-varying amplitude along with their derivatives is considered for a harmonic complex-valued signal given with an additive noise. Asymptotic minimax lower bounds are derived for the mean-squared errors of estimation provided that the phase and amplitude are arbitrary piece-wise differentiable functions of time. It is shown that these lower bounds are different only in constant factors from the optimal upper bounds of mean-squared errors of estimates given by the generalized local polynomial periodogram. The time-varying phase and amplitude are derived which are “ worst ”, respectively, for estimation of the Instantaneous Frequency, amplitude and their derivative. These “ worst ” functions can be applied in order to test the accuracy of algorithms used for estimation of the Instantaneous Frequency and amplitude.
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Instantaneous Frequency estimation using higher order l wigner distributions with data driven order and window length
IEEE Transactions on Information Theory, 2000Co-Authors: Ljubisa Stankovic, Vladimir KatkovnikAbstract:The L-Wigner distributions are defined in order to improve the concentration of signal's time-Frequency representation. For a finite distribution order and nonlinear Instantaneous Frequency (IF) it gives biased IF estimates. In the case of noisy signals the optimal window length and distribution order depend on the noise variance and unknown IF. In this article an adaptive IF estimator with the time-varying and data-driven window length and distribution order is developed. Based on the analysis that has been done here, lower order time-Frequency distributions are introduced.
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discrete time local polynomial approximation of the Instantaneous Frequency
IEEE Transactions on Signal Processing, 1998Co-Authors: Vladimir KatkovnikAbstract:The local polynomial approximation (LPA) of the time-varying phase is used to develop a new form of the Fourier transform and the local polynomial periodogram (LPP) as an estimator of the Instantaneous Frequency (IF) /spl Omega/(t) of a harmonic complex-valued signal. The LPP is interpreted as a time-Frequency energy distribution over the t-(/spl Omega/(t), /spl Omega//sup 1/(t)),...,/spl Omega//sup m-1/(t) space, where m is a degree of the LPA. The variance and bias of the estimate are studied for the short- and long-time asymptotic behavior of the IF estimates. In particular, it is shown that the optimal asymptotic mean squared errors of the estimates of /spl Omega//sup k-1/(t) have orders O(N/sup -(2k+1)/) and O(N/sup -/2(m-k+1)/2m+3), k=1.2,...,m, respectively, for a polynomial /spl Omega/(t) of the degree m-1 and arbitrary smooth /spl Omega/(t) with a bounded mth derivative.
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algorithm for the Instantaneous Frequency estimation using time Frequency distributions with adaptive window width
IEEE Signal Processing Letters, 1998Co-Authors: Ljubisa Stankovic, Vladimir KatkovnikAbstract:A method for minimization of the mean square error (MSE) of the Instantaneous Frequency estimation using time-Frequency distributions, in the case of a discrete optimization parameter, is presented. It does not require a knowledge of the estimation bias. The method is illustrated on adaptive window width determination in the Wigner distribution.
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local polynomial approximation of the Instantaneous Frequency asymptotic accuracy
Signal Processing, 1996Co-Authors: Vladimir KatkovnikAbstract:Abstract The local polynomial approximation of the time-varying phase is used in order to estimate the Instantaneous Frequency and its derivatives for a case of a complex harmonic signal. The considered estimators are high-order generalization of the short-time Fourier transform and the Wigner-Ville distribution. The asymptotic variance and bias of the estimates are obtained in order to evaluate the accuracy and the tracking ability of the algorithms. The comparative study of the algorithms is presented.
Niusha Sarkhosh - One of the best experts on this subject based on the ideXlab platform.
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amplitude independent photonic Instantaneous Frequency measurement with improved sensitivity
IEEE Photonics Journal, 2012Co-Authors: Niusha Sarkhosh, Hossein Emami, Arnan MitchellAbstract:A technique for improving the sensitivity of a class of broadband RF photonic Instantaneous Frequency measurement (IFM) systems is proposed and practically demonstrated. The technique utilizes lock-in amplification to isolate the desired signal from background noise. The demonstration is conducted on a dual orthogonal measurement IFM system utilizing multiple wavelengths and a transversal Hilbert transform achieving independent amplitude and Frequency measurements over a multioctave bandwidth with a sensitivity of $-$ 37 dBm. This performance is comparable with traditional electronic IFM receivers. The successful application of this lock-in approach to this multichannel photonic system illustrates its flexibility and indicates that it should be applicable to even more sophisticated systems.
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Instantaneous Frequency measurement system using optical mixing in highly nonlinear fiber
Optics Express, 2009Co-Authors: Mark Pelusi, Niusha Sarkhosh, Hossei Emami, Enjami J Eggleto, Arna MitchellAbstract:A broadband photonic Instantaneous Frequency measurement system utilizing four-wave mixing in highly nonlinear fiber is demonstrated. This new approach is highly stable and does not require any high-speed electronics or photodetectors. A first principles model accurately predicts the system response. Frequency measurement responses from 1 to 40 GHz are demonstrated and simple reconfiguration allows the system to operate over multiple bands.
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amplitude independent rf Instantaneous Frequency measurement system using photonic hilbert transform
Optics Express, 2008Co-Authors: Hossein Emami, Lam Anh Bui, Niusha Sarkhosh, Arnan MitchellAbstract:A photonic Instantaneous Frequency measurement system capable of measuring both RF Frequency and power simultaneously, is conceived and practically demonstrated. This system employs an RF photonic Hilbert transformer together with low-cost, low-Frequency photo-detectors to obtain two orthogonal DC measurements. This system exhibits a Frequency range of 1-10 GHz. Wider Frequency range can be achieved through integration.
