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US 4,069,468 AGranted
Doppler spectral measurement
AssigneeRaytheon Company
InventorJames F. Bartram
Life of this patent
Estimating the term…
Abstract
A system for Doppler frequency measurement, responsive to spectral modulation induced by a reverberant and nonlinear radiation transmissive region such as the ocean, and composed of a Fourier transformer for providing digitally the spectral lines for a set of samples of a Doppler signal, a circuit for obtaining the logarithm of the power spectrum, weighting of the logarithm by othogonal functions, and an arithmetic combination of components of the weighted logarithm.
Claims5
A Doppler measurement system comprising:
- means for sampling a signal received during a predetermined interval of time, said means providing a predetermined number of samples of said received signal during said predetermined interval of time;
- means for obtaining the power spectrum of a set of said samples consisting of said predetermined number of samples;
- means coupled to said power spectrum means for forming the logarithm of said spectrum;
- means coupled to said logarithmic means for multiplying output signals thereof by orthogonal function factors;
- and
- means coupled to said multiplying means for combining products of said multiplying means to produce a component of a Doppler frequency.
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In combination:
- means coupled to a medium propagative of radiant energy for producing echoes of radiant energy therefrom;
- means synchronized to said echo producing means for filtering a carrier frequency of said echoes;
- means coupled to said filtering means for providing samples of said echo having a frequency spectrum substantially centered about said carrier frequency;
- means for transforming a set of said samples to provide a set of orthogonal functions related to said set of samples;
- means coupled to said transforming means for taking the logarithm of said orthogonal functions;
- and
- means coupled to said logarithmic means for forming the weighted summation of said logarithms of said orthogonal functions to provide Doppler data of said echoes.
4 more elements
Dependencies are inferred from the claim text.