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US4313170A
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Autocorrelation side lobe reduction device for phase-coded signals
Assignee: United States Department of the Navy
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Filing: 1980-06-23
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Granted: 1982-01-26
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Expires: 2000-06-23
Abstract
Abstract A pulse compression decoder which oversamples by two the signal elements of a received phase-coded signal, performs a pairwise average on the signal elements at intervals equal to 1/2 the width of a signal element, reverse-codes the pairwise averages, combines the pairwise averages to form a sub-accumulation signal, and performs a pairwise average on the sub-accumulation signals at intervals equal to 1/2 the width of a signal element to produce a compressed pulse having a high peak-to-side lobe ratio.
Inventors
- 👤 Bernard L. Lewis
- 👤 Frank F. Kretschmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:26
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/284; G01S13/288
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
202 words
A decoder for decoding groups of N 2 sequentially applied signal elements reflected from a reflector element and which have been previously encoded by a polyphase function, where N is an integer, with each group differing from the preceding group by the addition of a new signal element to one end of the group and the deletion of a signal element from the other end of the group, comprising: oversample-averaging means for adding each of the signal elements of each group to itself at one instant of time to form a first averaged signal having N 2 signal elements and to the corresponding signal elements of a next applied group at another instant of time to form a second averaged signal having N 2 signal elements; multiplier means for impressing phase rotations on the N 2 signal elements of each averaged signal equal in magnitude but opposite in direction to the phase rotations impressed on the transmitted signal; summing means for adding together the phase-rotated signal elements of each averaged signal to form a sub-accumulation signal; and averaging window means for adding each sub-accumulation signal to a next generated sub-accumulation signal to produce a compressed pulse having a high peak-to-side lobe ratio.
Claim 2
Dependent Claim
202 words
A decoder for decoding groups of N 2 sequentially applied signal elements reflected from a reflector element and which have been previously encoded by a polyphase function, where N is an integer, with each group differing from the preceding group by the addition of a new signal element to one end of the group and the deletion of a signal element from the other end of the group, comprising: oversample-averaging means for adding each of the signal elements of each group to itself at one instant of time to form a first averaged signal having N 2 signal elements and to the corresponding signal elements of a next applied group at another instant of time to form a second averaged signal having N 2 signal elements; multiplier means for impressing phase rotations on the N 2 signal elements of each averaged signal equal in magnitude but opposite in direction to the phase rotations impressed on the transmitted signal; summing means for adding together the phase-rotated signal elements of each averaged signal to form a sub-accumulation signal; and averaging window means for adding each sub-accumulation signal to a next generated sub-accumulation signal to produce a compressed pulse having a high peak-to-side lobe ratio.
Claim 3
Dependent Claim
56 words
The decoder recited in claim 1 wherein the oversample-averaging means includes: delay means having 2 N 2 distributed outputs for producing a uniform delay between adjacent ones of successive outputs equal to half the width of a signal element, and signal-combining means coupled to the delay means for combining signals from successive pairs of outputs thereof.
Claim 4
Dependent Claim
23 words
The decoder recited in claim 2 wherein the oversample-averaging means includes: dividing means coupled to the signal-combining means for halving the combined signals.
Claim 5
Dependent Claim
52 words
The decoder recited in claim 2 wherein: the delay means includes 2 N 2 stages of a shift register with an output terminal at every stage; and the signal-combining means includes N 2 adders coupled respectively to successive pairs of output terminals of the 2 N 2 stages of the shift register.
Claim 6
Dependent Claim
22 words
The decoder recited in claim 4 wherein the multiplier means includes: N 2 complex multipliers coupled respectively to the N 2 adders.
Claim 7
Dependent Claim
54 words
The decoder recited in claim 1 wherein the averaging window means includes: delay means having two distributed outputs for producing a uniform delay between the two outputs equal to half the width of a signal element; and signal combining means coupled to the delay means for combining signals from successive pairs of outputs thereof.
Claim 8
Dependent Claim
25 words
The decoder recited in claim 6 wherein the averaging window means includes: dividing means coupled to the signal combining means for halving the combined signals.
Claim 9
Dependent Claim
44 words
The decoder recited in claim 6 wherein: the delay means includes two stages of a shift register with an output terminal at each stage; and the signal-combining means includes an adder coupled to the output terminals of the two stages of the shift register.
Claim 10
Independent Claim
192 words
A method of decoding groups of N 2 sequentially applied signal elements reflected from a reflector element and which have been previously encoded by a polyphase function, where N is an integer, with each group differing from the preceding group by the addition of a new signal element to one end of the group and the deletion of a signal element from the other end of the group, comprising the steps of: adding each of the signal elements of each group to itself at one instant of time to form a first averaged signal having N 2 signal elements and to the corresponding signal elements of the next applied group at another instant of time to form a second averaged signal having N 2 signal elements; impressing phase rotation on the N 2 signal elements of each averaged signal equal in magnitude but opposite in direction to the phase rotations impressed on the transmitted signal; adding together the phase-rotated signal elements of each averaged signal to form a sub-accumulation signal; and adding each sub-accumulation signal to a next generated sub-accumulation signal to produce a compressed pulse having a high peak-to-side lobe ratio.
Claim 11
Independent Claim
192 words
A method of decoding groups of N 2 sequentially applied signal elements reflected from a reflector element and which have been previously encoded by a polyphase function, where N is an integer, with each group differing from the preceding group by the addition of a new signal element to one end of the group and the deletion of a signal element from the other end of the group, comprising the steps of: adding each of the signal elements of each group to itself at one instant of time to form a first averaged signal having N 2 signal elements and to the corresponding signal elements of the next applied group at another instant of time to form a second averaged signal having N 2 signal elements; impressing phase rotation on the N 2 signal elements of each averaged signal equal in magnitude but opposite in direction to the phase rotations impressed on the transmitted signal; adding together the phase-rotated signal elements of each averaged signal to form a sub-accumulation signal; and adding each sub-accumulation signal to a next generated sub-accumulation signal to produce a compressed pulse having a high peak-to-side lobe ratio.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |