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US 5,508,605 AGranted
Method for measuring RF pulse frequency
AssigneeAlliedSignal Inc.
InventorsPei-Hwa Lo, Elliott J. Greene
Life of this patent
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Abstract
A method for measuring the frequency of a stream of RF pulses using multi-purpose, commercial-off-the-shelf test devices, such as an RF signal down converter, a digitizer and a signal processor. The method is based on digital signal processing and determining the zero-crossings of the signal using signal interpolation of the pulse points. The method is suitable for real-time calculations of the frequency.
Claims2
A method for measuring the carrier frequency of a stream of RF pulses comprising:
- (a) down converting said RF pulses to a pulse stream having an intermediate carrier frequency by taking the difference between the carrier frequency of said RF pulses and the carrier frequency of a control frequency;
- (b) digitizing said pulse stream;
- (c) extracting pulse points and baseline data of a sample from said pulse stream;
- (d) subtracting said baseline data from said pulse points;
- (e) locating initial points in time before and after each zero crossing within a time interval, subdividing said time interval and repetitively interpolating said initial points using Sin(X)/X to find time points before and after a zero crossing within a specified time accuracy range;
- (f) calculating the period of the carrier frequency of said pulse stream signal from said determined zero-crossing times;
- (g) calculating the carrier frequency of said pulse stream signal from said calculated period;
- and
- (h) calculating the RF pulse stream carrier frequency by summing said calculated intermediate carrier frequency with said control carrier frequency.
6 more elements
Dependencies are inferred from the claim text.