Une nouvelle classe d'opérateurs de Teager-Kaiser multidimensionnels basée sur les dérivées directionnelles d'ordre supérieur

This work aims at introducing some energy operators linked to Teager-Kaiser energy operator and its associated higher order versions and expand them to multidimensional signals. These operators are very useful for analyzing oscillatory signals with time-varying amplitude and frequency (AM-FM). We prove that gradient tensors combined with Kronecker powers allow to express these operators by directional derivatives along any n-D vector. In particular, we show that the construction of a large class of non linear operators for AM-FM multidimensional signal demodulation is possible. Also, a new scalar function using the directional derivative along a vector giving the ”sign” of the frequency components is introduced. An application of this model to local n-D AM-FM signal is presented and related demodulation error rates estimates. To show the effectiveness and the robustness of our method in term of envelope and frequency components extraction, results obtained on synthetic and real data are compared to multi-dimensional energy separation algorithm and to our recently introduced n-D operator

Estimation de l'enveloppe et de la fréquence locales par les opérateurs de Teager-Kaiser en interférométrie en lumière blanche.

In this work, a new method for surface extraction in white light scanning interferometry (WLSI) is introduced. The proposed extraction scheme is based on the Teager-Kaiser energy operator and its extended versions. This non-linear class of operators is helpful to extract the local instantaneous envelope and frequency of any narrow band AM-FM signal. Namely, the combination of the envelope and frequency information, allows effective surface extraction by an iterative re-estimation of the phase in association with a new correlation technique, based on a recent TK crossenergy operator. Through the experiments, it is shown that the proposed method produces substantially effective results in term of surface extraction compared to the peak fringe scanning technique, the five step phase shifting algorithm and the continuous wavelet transform based method. In addition, the results obtained show the robustness of the proposed method to noise and to the fluctuations of the carrier frequency

Optoelectronic Oscillators

Patrice Salzenstein (2011). Optoelectronic Oscillators, Optoelectronic Devices and Properties, Oleg Sergiyenko (Ed.), ISBN: 978-953-307-204-3, InTech, Available from: http://www.intechopen.com/articles/show/title/optoelectronic-oscillatorsOptoelectronic devices impact many areas of society, from simple household appliances and multimedia systems to communications, computing, spatial scanning, optical monitoring, 3D measurements and medical instruments. This is the most complete book about optoelectromechanic systems and semiconductor optoelectronic devices; it provides an accessible, well-organized overview of optoelectronic devices and properties that emphasizes basic principles

Optoelectronic Oscillators Phase Noise and Stability Measurements

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Low uncertainty determined by modern approach for high precision optoelectronic phase noise measurements

International audienceUncertainty on phase noise is calculated by modern approach for an optoelectronic measurement system. The final global uncertainty on the spectral density of phase noise determined by this method is lower than 2 dB

Realization of a 5 and 10 MHz High Performance Isolation Distribution Amplifier for short term frequency stability measurements of frequency sources

International audienceOur Laboratoire National d'Essai (LNE) associate laboratory is accredited to deliver calibration certificates in the short term domain. For spectral density of phase noise and short term frequency stability measurements, it is necessary to have the best reference source signals. However, the noise of the distribution amplifier has to be the weakest possible in order to keep the lowest noise floor. In order to deliver references signals, we achieve a high performances distribution amplifier. In terms of Allan variance, performance of the realized four channels distribution amplifier is respectively better than sigmay(to=1s) = 1,4.10-14 and 7,3.10-15 at 5 and 10 MHz. The intrinsic spectral density of phase noise is then better than Sphi(1Hz) = –141,4 dB.rad²/Hz at 5 MHz and –141 dB.rad²/Hz at 10 MHz with a 1/f slope

Applications of the optical fiber to the generation and to the measurement of low-phase-noise microwave signals

The optical fiber used as a microwave delay line exhibits high stability and low noise and makes accessible a long delay (>100 microseconds) in a wide bandwidth (about 40 GHz, limited by the optronic components). Hence, it finds applications as the frequency reference in microwave oscillators and as the reference discriminator for the measurement of phase noise. The fiber is suitable to measure the oscillator stability with a sensitivity of parts in 1E-12. Enhanced sensitivity is obtained with two independent delay lines, after correlating and averaging. Short-term stability of parts in 1E-12 is achieved inserting the delay line in an oscillator. The frequency can be set in steps multiple of the inverse delay, which is in the 10-100 kHz region. This article adds to the available references a considerable amount of engineering and practical knowledge, the understanding of 1/f noise, calibration, the analysis of the cross-spectrum technique to reduce the instrument background, the phase-noise model of the oscillator, and the experimental test of the oscillator model.Comment: 23 pages, 13 figures, 41 reference

Hidden fuzzy Markov chain model with K discrete classes

International audienceThis paper deals with a new unsupervised fuzzy Bayesian segmentation method based on the hidden Markov chain model, in order to separate continuous from discrete components in the hidden data. We present a new F-HMC (fuzzy hidden Markov chain) related to three hard classes, based on a general extension of the previously algorithms proposed. For a given observation, the hidden variable owns a density according to a measure containing Dirac and Lebesgue components. We have performed our approach in the multispectral context. The hyper-parameters are estimated using a Stochastic Expectation Maximization (SEM) algorithm. We present synthetic simulations and also segmentation results related to real multi-band data

Investigation in acousto-optic laser stabilization for crystal resonator-based optoelectronic oscillators

International audiencePotentialities are investigated for using acousto-optic cells based on a TeO2 crystal to stabilize a microwave signal generated by an optoelectronic oscillator. Bulk acoustic waves at two radio frequencies (RF) near 60 MHz are launched in the two identical cells providing a required locking on of a microwave signal. Differences between RF signals are up to 400 kHz to follow quality factor of the optic resonator typically in the range of 5×108. Critical alignment of the two cells is performed thanks to an extraordinary polarized laser beam launched at a very low Bragg angle of light incidence. Moreover, the system is operating for any resonator to be inserted into the optoelectronic oscillator with a Q factor in the range of 2×107−1011