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AssigneeNational Research Development Corporation
InventorsMichael Alldritt, Robin Jones, Christopher J. Oliver, John M. Vaughan
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A method of, and apparatus for, processing a digital electric signal composed of a train of discrete uniformly or non-uniformly shaped pulses to recover spectral information contained in the spacings between the pulses, in which the digital signal is applied to a SAW spectrum analyzer arranged to produce output signals the envelopes of which represent the power spectrum over a selected frequency range of constituent sample lengths of the digital signal, and the required spectral information then derived from these output signals, for example by integration thereof over a period of time. The technique may be used in conjunction with a laser Doppler velocity measurement system in which each pulse of the digital signal represents the detection of a photon scattered from a moving object or particle in a scattering volume illuminated by laser light, the spacing between the pulses containing information regarding the velocity of movement of the object or particles under observation.
A method of processing a digital electrical signal from a photon-counting detector composed of a train of discrete pulses each representing the detection of an individual photon, to recover spectral information contained in the spacings between the pulses, the method comprising the steps of applying the said digital signal to a surface acoustic wave (SAW) spectrum analyzer arranged to produce output signals which represent the power spectrum of constituent sample lengths of the digital signal over a selected frequency range, and integrating a plurality of said output signals to produce an integrated output signal representing the overall power spectrum, over at least a part of said selected frequency range, of a plurality of constituent sample lengths of the digital signal.
Dependencies are inferred from the claim text.