Analysis Of Chirp Signals Research Articles

High resolution time-frequency representation for chirp signals using an adaptive system based on duffing oscillators

This paper presents a novel methodology to estimate the frequency shift in chirp signals with SNRs as low as −17 dB through the use of an adaptive array of Duffing oscillators. The system used here is an array of five Duffing oscillators with each oscillator's response enhanced through a correlation with the reference signal. As a final result, a time-frequency depiction is provided by the Duffing array for further analysis of chirp signals.Using computer simulated experiments, it is found that the analysis of chirp signals with low SNR by means of the Duffing oscillator shows a markedly better performance than the conventional methods of time-frequency analysis. To this end, the results obtained from the proposed Duffing method are compared against some recent techniques in time-frequency analysis.Furthermore, to strengthen the proposed representation, Monte Carlo simulation is used.

Time-frequency representation of multicomponent chirp signals

This work deals with the analysis of chirp signals by means of time-frequency representation. We propose a chirp adapted time-frequency representation (CA) in which the interferences are significantly reduced. This method is applied to the analysis of acoustic echoes of a sphere target. Comparison of the results to other types of time-frequency distribution of the Cohen's class shows that the identification of the signal features with CA representation is clearer than with other types of bilinear time-frequency distributions.

ANALYSIS OF MULTICOMPONENT CHIRP SIGNALS USING FREQUENCY-SHEAR REPRESENTATION

This paper is concerned with the problem of multicomponent chirp signal analysis. The traditional analysis tool is time-frequency distribution which has been paid more attention in deterministic nonstationary signal processing. However, for chirp signals, it is difficult to find a best time-frequency representation that has high auto component concentration and cross-term suppression. Generally, any time-frequency representation based on rectangular resolution cell will not result in good performance for signals with time-varying frequency content. In this paper we propose a new representation for analyzing multicomponent chirp signals using resolution cell that shears in the timefrequency plane. In our approach, the kernel function with its shape adapted to the local structure of the chirp signal is used so that the signal components can be clearly mapped onto the frequency-shear plane. It is shown that the frequency-shear representation can reduce spurious values and concentrate on the auto components. Several signals including sinusoidal signals and chirp signals are analyzed and simulated using the proposed approach in comparison with the results by the Wigner distribution.