| 摘要 |
A method and apparatus for determining the value of a Doppler frequency shift component DELTA f present in a signal f +/- DELTA f employing a correlation process which utilizes the Mellin transform and is scale invariant. The location of the correlation peak in the reference coordinate system used provides a measure of the magnitude of DELTA f. The sequence of steps involved in the correlation process when optical apparatus is used include forming a transmittance pattern of the signal f +/- DELTA f, which has a horizontal scale that is the natural log of the time scale of the original signal, forming a similarly scaled transmittance pattern of the reference signal, f, and utilizing the first patttern in the input plane of a frequency plane correlator that has a holographic matched spatial filter that is produced from the second pattern and contains a term corresponding to the conjugate of the Mellin transform of the reference signal in its frequency plane.
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