In case of a strong frequency modulated interference in a spread spectrum communication system, the interference can be effectively suppressed by applying a time-varying notch filter with its zero(s) placed at an instantaneous frequency (IF) estimate of the interference. In this paper, we present the use of a timevarying autoregressive model based IF estimator in such a scenario. We model the r...

Based upon the sparse array composed of cluster SAR satellites, this paper analyzes the space-time and space-frequency characteristic of the received signal in detail, and proposes an algorithm for the moving targets detection and imaging based on array signal processing and Wigner-Ville Distribution (WVD). The results of theoretical analysis and simulation show that the cluster SAR system can ...

This paper presents a new approach based on spatial time–frequency averaging for separating signals received by a uniform linear antenna array. In this approach, spatial averaging of the time–frequency distributions (TFDs) of the sensor data is performed at multiple time–frequency points. This averaging restores the diagonal structure of the source TFD matrix necessary for source separation. Wi...

Time-frequency distributions have been used extensively for nonstationary signal analysis, they describe how the frequency content of a signal is changing in time. The Wigner-Ville distribution (WVD) is the best known. The draw back of WVD is cross-term artifacts. An alternative to the WVD is Gabor transform (GT), a signal decomposition method, which displays the time-frequency energy of a sign...

In this paper, we consider the analysis of polynomial FM signals corrupted by additive heavy-tailed noise. Standard timefrequency techniques fail to analyze such signals. For that, we propose here a new technique, named the robust polynomial WignerVille distribution (r-PWVD) to handle this case. We show that this representation outperforms the robust Wigner-Ville distribution (rWVD) and the rob...

One of the applications with nonlinear nonstationary signals lies in mobile communications where nonlinear information bearing signals are faded by the time-varying propagation medium. Consequently, the envelope of the received signal is often modelled by a Rayleigh distribution. This Rayleigh fading severely degrades the performance of the mobile radio transmission system. Diversity reception ...

In this article we propose a modification to the combinatorial hidden Markov model developed in [1] for tracking partial frequency trajectories. We employ the Wigner-Ville distribution and Hough transform in order to (re)estimate the frequency and chirp rate of partials in each analysis frame. We estimate the initial phase and amplitude of each partial by minimizing the squared error in the tim...

In this paper we present two methodologies to generate heart rate variability (HRV) signals characterized by controlled and real-like time-frequency (TF) structure to be used to assess different methods of non-stationary HRV analysis. The synthesized signals are stochastic processes whose TF structure is predetermined by choosing either the time-course of the instantaneous frequencies and power...