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High-accuracy, low-distortion time-frequency analysis of signals using rotated-window spectrograms
High-accuracy, low-distortion time-frequency analysis of signals using rotated-window spectrograms
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机译:使用旋转窗口频谱图对信号进行高精度,低失真的时频分析
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摘要
A speech processing and analysis apparatus and method (18) for generating a time-frequency distribution of a speech signal which combines a set of spectrograms with varying window lengths and orientations to provide a parameter-less time-frequency distribution having good joint time and frequency resolution at all angular orientations are disclosed. The analysis window of a spectrogram is rotated relative to the frequency components of the signal by preprocessing using a Fractional Fourier Transform to form rotated window spectrograms. In particular, to form the rotated window spectrogram, the signal 24 is initially pre-processed (1) using a Fractional Fourier Transform of angle α. The spectrogram time-frequency distribution of the pre-processed signal is then computed (2) using analysis window h(t) and then rotated (3) by angle -α. The geometric mean of a set of rotated window spectrograms, which are indexed by both the analysis window length and the angular orientation of the window relative to the signal's time-frequency features, may then be computed to form a combination of rotated window spectrograms.
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