Hardy–Sobolev derivatives of phase and amplitude, and their applications
Hardy–Sobolev derivatives of phase and amplitude, and their applications
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DOI:
10.1002/mma.2632
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发表时间:
2012-11
影响因子:
2.9
通讯作者:
P. Dang;Tao Qian;Yan Yang
中科院分区:
文献类型:
--
作者:
P. Dang;Tao Qian;Yan Yang
In time‐frequency analysis, there are fundamental formulas expressing the mean and variance of the Fourier frequency of signals, s, originally defined in the Fourier frequency domain, in terms of integrals against the density | s(t) | 2 in the time domain. In the literature, the existing formulas are only for smooth signals, for it is the classical derivatives of the phase and amplitude of the signals that are involved. The two representations of the covariance also rely on the classical derivatives and thus are restrictive. In this fundamental study, by introducing a new type of derivatives, called Hardy–Sobolev derivatives, we extend the formulas to signals in the Sobolev space that do not usually have classical derivatives. We also investigate the corresponding formulas for periodic (infinite discrete) and finite discrete signals. Copyright © 2012 John Wiley & Sons, Ltd.