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Journal ArticleDOI

Application of the envelope-phase representation in some non-linear noise problems†

01 Mar 1968-International Journal of Electronics (Taylor & Francis Group)-Vol. 24, Iss: 3, pp 201-209
TL;DR: It is shown here that this approach is equally good for the more general problem of evaluating the output power‡ series of a non-linearity of either single-valued or double-valued type.
Abstract: The paper discusses an extension of some of the earlier works of the author and his student on a procedure for evaluating the transmission properties of gaussian signals through non-linear devices. It is based on the application of the envelope-phase representation of such signals and subsequent application of the Fourier series expansion of the instantaneous output of the non-linearity. The earlier investigations were concerned mainly with the evaluation of the input-output cross-power‡ terms. It is shown here that this approach is equally good for the more general problem of evaluating the output power‡ series of a non-linearity of either single-valued or double-valued type. An application of those computations in the field of nonlinear filtering is discussed.
References
More filters
Journal ArticleDOI
TL;DR: Application is made to the interesting special cases of conventional cross-correlation and autocorrelation functions, and Bussgang's theorem is easily proved.
Abstract: If and only if the inputs to a set of nonlinear, zero-memory devices are variates drawn from a Gaussian random process, a useful general relationship may be found between certain input and output statistics of the set. This relationship equates partial derivatives of the (high-order) output correlation coefficient taken with respect to the input correlation coefficients, to the output correlation coefficient of a new set of nonlinear devices bearing a simple derivative relation to the original set. Application is made to the interesting special cases of conventional cross-correlation and autocorrelation functions, and Bussgang's theorem is easily proved. As examples, the output autocorrelation functions are simply obtained for a hard limiter, linear detector, clipper, and smooth limiter.

580 citations

Journal ArticleDOI
TL;DR: By using the pre-envelope, the envelope of the output of a linear filter is easily calculated, and this is used to compute the first probability density for the envelopes of an arbitrary linear filter when the input is an arbitrary signal plus Gaussian noise.
Abstract: Rice's formula ^1 for the "envelope" of a given signal is very cumbersome; in any case where the signal is not a single sine wave, the analytical use and explicit calculation of the envelope is practically prohibitive. A different formula for the envelope is given herein which is much simpler and easier to handle analytically. We show precisely that if \hat{u}(t) is the Hilbert transform of u(t) , then Rice's envelope of u(t) is the absolute value of the complex-valued function u(t) + i \hat{u}(t) . The function u + i\hat{u} is called the pre-envelope of u and is shown to be involved implicitly in some other usual engineering practices. The Hilbert transform \hat{u} is then studied; it is shown that \hat{u} has the same power spectrum as u and is uncorrelated with u at the same time instant. Further, the autocorrelation of the pre-envelope of u is twice the pre-envelope of the autocorrelation of u . By using the pre-envelope, the envelope of the output of a linear filter is easily calculated, and this is used to compute the first probability density for the envelope of the output of an arbitrary linear filter when the input is an arbitrary signal plus Gaussian noise. An application of pre-envelopes to the frequency modulation of an arbitrary waveform by another arbitrary waveform is also given.

239 citations

Book
01 Jan 1965

169 citations