Method for efficient sampling in a correlator
First Claim
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1. A method of correlating signal portions comprising:
- a) receiving an input signal having code chips;
b) converting said input signal to a representation having a first integer number of consecutive representation segments, each of said representation segments having a second integer number of samples;
c) storing said first integer number of representation segments in memory;
d) generating a replica segment having said second integer number of samples; and
e) correlating each of said representation segments with said replica segment to produce a correlation result;
whereinsaid samples of each of said representation segments and of said replica segment occur at a rate which produces a sampling pattern on each of said replica and representation segments that precesses relative to said code chips, but is substantially stationary relative to said replica and representation segments.
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Abstract
A direct sequence spread spectrum receiver samples an incoming signal at a low non-integer sample rate relative to the input data rate. The sample rate is an integer rate relative to a defined data segment. As multiple segments are sampled, the non-integer sample rate causes bit/chip samples to process relative to the incoming data. Because the sample rate is an integer relative to a data segment, the samples are substantially stationary relative to each segment. Such a method is useful in global positioning satellite (GPS) signal processing wherein the time to first fix is minimized by having to correlate fewer sample points in the acquisition process.
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13 Claims
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1. A method of correlating signal portions comprising:
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a) receiving an input signal having code chips; b) converting said input signal to a representation having a first integer number of consecutive representation segments, each of said representation segments having a second integer number of samples; c) storing said first integer number of representation segments in memory; d) generating a replica segment having said second integer number of samples; and e) correlating each of said representation segments with said replica segment to produce a correlation result;
whereinsaid samples of each of said representation segments and of said replica segment occur at a rate which produces a sampling pattern on each of said replica and representation segments that precesses relative to said code chips, but is substantially stationary relative to said replica and representation segments. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification