As the useful time-frequency tool, the Fractional Fourier Transform (FRFT) and the Short Time Fourier Transform (STFT) have a great development of signal recognition. And the Reduced Fractional Fourier Transform (RFRFT) was recently proposed and has been used in the recognition and estimation of chirp signals. A new method based on STFT and RFRFT is presented for radar signals modulation recogn...

We study the connection between STFT multipliers A1⊗mg1,g2 having windows g1,g2, symbols a(x,ω)=(1⊗m)(x,ω)=m(ω), (x,ω)∈R2d, and Fourier Tm2 with symbol m2 on Rd. find sufficient necessary conditions m,m2 g1,g2 for equality Tm2=A1⊗mg1,g2. For m=m2 former holds only particular choices of window functions in modulation spaces, whereas it never occurs realm Lebesgue spaces. In general, multiplier A...

Shift and rotation invariance properties of linear time-frequency representations are investigated. It is shown that among all linear time-frequency representations, only the short-time Fourier transform (STFT) family with the Hermite–Gaussian kernels satisfies both the shift invariance and rotation invariance properties that are satisfied by the Wigner distribution (WD). By extending the time-...

there are two methods for identifying formation interface in oil wells: core analysis, which is a precise approach but costly and time consuming, and well logs analysis, which petrophysists perform, which is subjective and not completely reliable. in this paper, a novel coupled method was proposed to detect the formation interfaces using gr logs. second approximation level (a2) of gr log gained...

A frequency grouping approach for multi-channel instantaneous blind source separation (I-BSS) of convolutive mixtures is proposed for a lower net residual inter-symbol interference (ISI) and inter-channel interference (ICI) than the conventional short-time Fourier transform (STFT) approach. Starting in the time domain, STFTs are taken with overlapping windows to convert the convolutive mixing p...

Frequency domain analyses in electromyographic (EMG) signals are frequently applied to assess muscle fatigue and similar variables. Moreover, Fourier-based approaches are typically used for investigating these procedures. Nonetheless, Fourier analysis assumes the signal as stationary which is unlikely during dynamic contractions. As an alternative method, wavelet-based treatments do not assume ...

This paper presents a new approach in the detection, localization, and classification of frequency and amplitude changes in nonstationary signal waveforms using a variable window shorttime Fourier Transform (STFT) known as ST in short and an Extended Complex Kalman Filter (CEKF). Unlike the fixed window STFT, the variable window Short-time Fourier Transform has excellent time-frequency resoluti...