نتایج جستجو برای: time frequency transform

تعداد نتایج: 2342512  

2009
Dinh-Tuan Pham Zaher El-Chami Alexandre Guérin Christine Servière

This paper presents the theoretical background for the Model Based Underdetermined Source Separation presented in [5]. We show that for a given frequency band, in contrast to customary assumption, the observed Short-Time Fourier Transform (STFT) ratio coming from one source is not constant in time, but is a random variable whose distribution we have obtained. Using this distribution and the Tim...

2014
Mrinal Sharma Meenakshi Sharma

Wavelet analysis is an exciting new method for solving difficult problems in mathematics, physics, and engineering, with modern applications. Wavelet transform of a function is the improved version of Fourier transform. In conventional Fourier transform, we use sinusoids for basis functions. It can only provide the frequency information. Temporal information is lost in this transformation proce...

1999
Hui CAO Ming LAI

With good time-frequency discrimination ability and flexible time-frequency windows, wavelet transform is now widely used to analysis various signals in time and frequency domain simultaneously. Because of the simple relation between wavelet spectra and local (evolutionary) power spectra of a signal, a new method based on wavelet transform to estimate the local power spectra of earthquake groun...

Journal: :JOURNAL OF THE JAPAN STATISTICAL SOCIETY 1997

2009
Mohammad Javad Dehghani

. In the power quality analysis non-stationary nature of voltage distortions require some precise and powerful analytical techniques. The time-frequency representation (TFR) provides a powerful method for identification of the non-stationary of the signals. This paper investigates a comparative study on two techniques for analysis and visualization of voltage distortions with time-varying ampli...

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