Analysis of trains of pulses
First Claim
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1. A method of analysing a received signal containing a train of pulses occurring at respective times of arrival, the method comprising:
- (a) forming a group of pulses such that pulses within the group have a substantially uniform pulse repetition interval within a range defined by predetermined minimum and maximum values; and
(b) calculating an average group pulse repetition interval by;
(i) for each of a plurality of pulses in the group, determining a respective approximate repetition interval;
(ii) determining a vector from each said approximate repetition interval by performing a linear mapping process such that the range between the predetermined minimum and maximum values is represented by an arc of a length which is less than or equal to π
,(iii) determining the angle of a vector sum of the determined vectors; and
(iv) performing an inverse of said mapping process to derive said average group pulse repetition interval from the angle of said vector sum.
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Abstract
Candidate moments within a pulse train are selected. For each such moment, it is determined whether pulses occur at uniform intervals both before and after the moment; if so, the relevant pulses are classified as belonging to a particular group. An accurate calculation of interpulse interval is carried out by working out the repetition interval from the times of arrival of the pulses relative to the candidate moment, and then taking a weighted angular average.
28 Citations
23 Claims
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1. A method of analysing a received signal containing a train of pulses occurring at respective times of arrival, the method comprising:
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(a) forming a group of pulses such that pulses within the group have a substantially uniform pulse repetition interval within a range defined by predetermined minimum and maximum values; and (b) calculating an average group pulse repetition interval by; (i) for each of a plurality of pulses in the group, determining a respective approximate repetition interval; (ii) determining a vector from each said approximate repetition interval by performing a linear mapping process such that the range between the predetermined minimum and maximum values is represented by an arc of a length which is less than or equal to π
,(iii) determining the angle of a vector sum of the determined vectors; and (iv) performing an inverse of said mapping process to derive said average group pulse repetition interval from the angle of said vector sum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 21, 22, 23)
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11. A method of analysing a received signal containing a train of pulses occurring at respective times of arrival, the method comprising:
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(I) selecting a candidate moment and calculating at least first and second predetermined time ranges respectively before and after the candidate moment; (II) for those pulses with times of arrival within said predetermined time ranges, deriving count values each associated with a respective time interval and each dependent on the number of such pulses for which the absolute difference between the time of arrival of the respective pulse and the candidate moment is substantially equal to an integer multiple of said time interval; and (III) if one of said count values exceeds a predetermined threshold, assigning the pulses associated with said one count value to a pulse group. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification