US 4,730,257 AGranted

Apparatus for analyzing signals, to obtain parameters of constituents

OwnerLai-wan M. Szetoinventor

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Abstract

An apparatus for analyzing a signal takes the Fourier Transform of both an original signal and a shifted signal, which has previously been subjected to a shift, for example a time shift, relative to the original signal. This gives sets of first and second frequency components corresponding respectively to the original signal and the shifted signal. The arguments of at least one pair of corresponding first and second frequency components are calculated, and subtracted to give a phase difference. From this phase difference, the frequency of the corresponding constituent of the original signal can be determined. Further, having obtained the frequency, one can calculate the initial phase and amplitude of the corresponding constituent of the original signal. The signal can vary temporally or spatially.

Claims24

Dependent claims

An apparatus, for use in analysing a signal, the apparatus comprising:

(i) delay means, for applying a delay to an original signal, to create a shifted signal and having an output;
(ii) first transform means for applying a Fourier Transform to an original signal, to create a plurality of first frequency components, and having an output;
(iii) second transform means connected to the output of the delay means, for applying a Fourier Transform to the shifted signal to create a plurality of second frequency components, the second transform means having an output for the second frequency components:
(iv) argument obtaining means connected to the outputs of the first and second transform means for obtaining the arguments of the corresponding first and second frequency components and having an output for said arguments;
(v) phase difference obtaining means, connected to the output of the argument obtaining means and having an output;
and
(vi) frequency obtaining means, connected to the output of the phase difference obtaining means, for obtaining the frequencies of the constituents of the original signal from said phase differences.

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Dependencies are inferred from the claim text.