A spectral correlation theory for cyclostationary time-series is introduced. It is established that a time-series is cyclostationary if and only if there exists a quadratic time-invariant transformation that generates spectral lines, and this is so if and only if the time-series exhibits spectral correlation. Fundamental properties of a characterizing spectral correlation function are developed...

Technology for classifying low probability of intercept (LPI) radar signals with speed and accuracy is critical cognitive communication research. We used time-frequency analysis (TFA) deep learning to classify 12 typical LPI signals. Traditional methods use the Choi-Williams distribution (CWD), which requires more than 500 times longer TFA generation time spectrogram method. In this paper, we s...

We address in this paper a unified presentation of previous works by A. Belouchrani, K. Abed-Meraim and co-authors about separation of FIR convolutive mixtures using (joint) block-diagonalization. We first present general equations in the stochastic context. Then the implementation of the general method is studied in practice and linked with previous works for stationary and non-stationary sour...

We address the problem of locating a transient source, such as an acoustic emission source, in a plate. We apply time-frequency analysis to the signals detected at a receiver. These highly dispersive and complex waveforms are measured for source-receiver separations ranging from 40 to 180 plate thicknesses and at frequencies such that 10 to 20 Rayleigh-Lamb branches are included. Reassigned, sm...

Wavelet transform is a powerful tool for analysing the problems arising in harmonic analysis, signal and image processing, sampling, filtering, so on. However, they seem to be inadequate representing those signals whose energy not well concentrated frequency domain. In pursuit of representations such signals, we propose novel time-frequency coined as quadratic-phase wave packet L2(R). The propo...

Această lucrare prezintă o metodă de măsura a conţinutului informaţional al reprezentării spectral Wigner-Ville a imaginilor Radar cu Apertura Sintetică (SAR), într-o abordare bazată pe imagete, care foloseţte măsura stohastică parametrică dată de Entropia Rényi. Pe baza conceptelor informaţionale definite de Flandrin, se efectuează o analiză locală a reprezentării timp-frecvenţă a unei imagete...

Due to the non-stationary, multicomponent nature of biomedical signals, the use of time-frequency analysis can be inevitable for these signals. The choice of the proper time-frequency distribution (TFD) that can reveal the exact multicomponent structure of biological signals is vital in many applications, including the diagnosis of medical abnormalities. In this paper, the instantaneous frequen...