Topic
Time–frequency analysis
About: Time–frequency analysis is a research topic. Over the lifetime, 5407 publications have been published within this topic receiving 104346 citations.
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TL;DR: This paper proposes a novel frequency-shift keying (FSK) demodulation method using short-time discrete Fourier transform (ST-DFT) analysis for low-Earth-orbit (LEO) satellite communication systems and proposes an efficient demodulated-algorithm frequency-sequence estimation (FSE) based on the Viterbi algorithm.
Abstract: This paper proposes a novel frequency-shift keying (FSK) demodulation method using short-time discrete Fourier transform (ST-DFT) analysis for low-Earth-orbit (LEO) satellite communication systems. The ST-DFT-based FSK demodulation method is simple and robust to a large and time-variant frequency offset because it expands the received signal in a time-frequency plane and demodulates it only by searching the instantaneous spectral peaks with no complicated carrier-recovery circuit. Two kinds of demodulation strategies are proposed: a bit-by-bit demodulation algorithm and an efficient demodulation-algorithm frequency-sequence estimation (FSE) based on the Viterbi algorithm. In addition, in order to carry out an accurate ST-DFT window synchronization, a simple DFT-based ST-DFT window-synchronization method is proposed.
35 citations
TL;DR: A chirp time–frequency representation for non-stationary signals is proposed, and—via a multi-window Gabor expansion—the corresponding evolutionary spectra is associated with it.
35 citations
TL;DR: In this paper, an accelerogram of the instantaneous phase of signal components referred to as an instantaneous frequency rate spectrogram (IFRS) is presented as a joint time-frequency distribution.
35 citations
TL;DR: In this paper, a time-frequency analysis of chirped femtosecond pulses using the Wigner distribution function is presented, which graphically obtain the instantaneous carrier frequency and the group delay of the chirping pulse using a peak-detection method.
Abstract: A time–frequency analysis of chirped femtosecond pulses using the Wigner distribution function is presented. We graphically obtain the instantaneous carrier frequency and the group delay of the chirped pulse using a peak-detection method. After confirming that the instantaneous carrier frequency of an ultra-short laser pulse defined by the derivative of the temporal phase is not generally supported by the optical frequency, we use the Wigner distribution to decompose the optical frequencies that mainly contribute to the pulse at a certain time. For this purpose, a chirped pulse with a double-peaked spectrum and one whose phase is distorted by third-order dispersion are analyzed with the peak-detection method. The Wigner distribution along with this graphical method successfully resolves the multicomponent frequencies that cannot be seen in the standard Fourier analysis.
35 citations
01 Oct 2006
TL;DR: A new macromodeling scheme for electrically long interconnects characterized by tabulated frequency responses, modeled as a superposition of multiple single-delay atoms, which are identified via a selective inversion of a Gabor transform of the raw frequency data.
Abstract: We introduce a new macromodeling scheme for electrically long interconnects characterized by tabulated frequency responses. The transfer function of the interconnect is modeled as a superposition of multiple single-delay atoms, which are identified via a selective inversion of a Gabor transform of the raw frequency data. Each atom is then approximated by a delayed rational function, leading to a highly-efficient SPICE-ready macromodel.
35 citations