Patent US4309769A successfully refreshed from Google Patents.
US4309769A
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Method and apparatus for processing spread spectrum signals
Assignee: Harris Corp
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Filing: 1980-02-25
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Granted: 1982-01-05
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Expires: 2000-02-25
Abstract
Abstract In order to avoid the need for individual RF down-converters in each channel of a spread spectrum adaptive array receiver, means are provided for frequency offsetting the received spread spectrum signals in each antenna array element from spread spectrum signals in the other array elements. The frequency offset signals are summed to form a broadband composite signal of spread spectrum signals separated from one another by the frequency offsets. After summing, the spread spectrum signals in the composite broadband signal are despread to form a narrowband composite signal having narrowband signals separated by the frequency offset. Since the resulting composite despread signal has a relatively narrow bandwidth, it can be passed through a single common receiver. Accordingly, the input to an adaptive array processor from the receiver is a low frequency relatively narrow signal. This significantly reduces the tracking requirements of the adaptive array processor and allows for significant reduction in costs, weight and size of the adaptive array processor in addition to the elimination of unnecessary RF down-converters.
Inventors
- 👤 Taliaferro H. Taylor, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:58
CPC Classifications
H; H04; H04K; H04K3/00; H04K3/20; H04K3/25; G; G01; G01S; G01S7/00; G01S7/02; G01S7/36; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/2605; H04B; H04B1/00; H04B1/69; H04K2203/00; H04K2203/30; H04K2203/32
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
94 words
A spread spectrum receiving system comprising: an antenna array having a plurality of elements for receiving a spread spectrum signal; means for frequency offsetting the spread spectrum signal in each array element from spread spectrum signals in the other array elements; means for summing the frequency offset signals to form a broadband composite signal of spread spectrum signals separated from one another by the frequency offsets; and means for despreading the spread spectrum signals of the broadband composite signal to form a first narrowband composite signal having narrowband signals separated by the frequency offset.
Claim 2
Dependent Claim
94 words
A spread spectrum receiving system comprising: an antenna array having a plurality of elements for receiving a spread spectrum signal; means for frequency offsetting the spread spectrum signal in each array element from spread spectrum signals in the other array elements; means for summing the frequency offset signals to form a broadband composite signal of spread spectrum signals separated from one another by the frequency offsets; and means for despreading the spread spectrum signals of the broadband composite signal to form a first narrowband composite signal having narrowband signals separated by the frequency offset.
Claim 3
Dependent Claim
32 words
A system as in claim 1, further comprising a common receiver coupled to the output of the despreading means for down-converting the frequency of the narrowband signals in the narrowband composite signal.
Claim 4
Dependent Claim
34 words
A system as in claim 1, wherein the despreading means comprises a mixer having a first input coupled to the output of the summing means and a second input for receiving a despreading signal.
Claim 5
Dependent Claim
30 words
A system as in claim 3, wherein the spread spectrum signal includes a PN sequence code, and the despreading signal utilizes this PN sequence code to produce the narrowband signals.
Claim 6
Dependent Claim
19 words
A system as in claim 4, wherein the PN sequence code is a fast code sequence C f (t).
Claim 7
Dependent Claim
62 words
A system as in claim 1, wherein the frequency offsetting means comprises a plurality of mixers MO 1 . . . MO n , one of said mixers being coupled to each array element, wherein each of said mixers MO 1 . . . MO n is also coupled to a frequency signal F 1 . . . F n , respectively.
Claim 8
Dependent Claim
21 words
A system as in claim 2, further comprising means coupled to the output of the receiver for removing the frequency offset.
Claim 9
Dependent Claim
52 words
A system as in claim 7, wherein the removing means includes a plurality of mixers MR 1 . . . MR n coupled in parallel to the output of the receiver, wherein each of said mixers is also coupled to a frequency signal F 1 . . . F n , respectively.
Claim 10
Dependent Claim
37 words
A system as in claim 7 or 8, further comprising an adaptive array processor coupled to the mixers MR 1 . . . MR n including removing the frequency offset components of the first narrowband composite signal.
Claim 11
Dependent Claim
35 words
A system as in claim 2, wherein the spread spectrum signal includes a PN fast code signal C f (t), and said receiving system further includes means for error tracking the PN fast code alignment.
Claim 12
Dependent Claim
65 words
A system as in claim 10, wherein the error tracking means includes an auxiliary channel coupled in parallel to the despreading means between the summing means and the common receiver, said auxiliary channel including means for multiplying the spread spectrum signals in the composite broadband signal by a despreading error function to produce a second composite narrowband signal for error tracking the PN fast code.
Claim 13
Dependent Claim
28 words
A system as in claim 11, wherein the despreading error function is: p(t)[C.sub.f (t+τ.sub.c)-C.sub.f (t-τ.sub.c)] where p(t) is a perturbational sequence and τ c is the chip time.
Claim 14
Dependent Claim
37 words
A system as in claim 11 or 12, wherein the error tracking means further includes a PN tracking demodulator coupled to the receiver output to generate a misalignment PN error signal based on the despreading error function.
Claim 15
Dependent Claim
23 words
A system as in claim 1, wherein the spread spectrum signals includes a PN slow coding sequence C s (t) for beam steering.
Claim 16
Dependent Claim
30 words
A system as in claim 14, wherein the PN slow coding sequence has a frequency of at least twice the frequency of a data rate of the spread spectrum signals.
Claim 17
Dependent Claim
47 words
A system as in claim 9, wherein the adaptive array processor includes a signal recognizer for detecting a slow coding sequence contained in the spread spectrum signals and means for adjusting the adaptive array processor for beam steering in accordance with the output of the signal recognizer.
Claim 18
Dependent Claim
23 words
A system as in claim 1, wherein the spread spectrum signal includes a chirp signal, and the despreading means includes a dechirp signal.
Claim 19
Independent Claim
94 words
A method comprising: receiving a spread spectrum signal in an antenna array having a plurality of elements to produce spread spectrum signals respectively in the elements; frequency offsetting the spread spectrum signals in each array element from spread spectrum signals in the other array elements; summing the frequency offset signals to form a broadband composite signal of spread spectrum signals separated from one another by the frequency offsets; and despreading the spread spectrum signals of the broadband composite signal to form a first narrowband composite signal having narrowband signals separated by the frequency offset.
Claim 20
Independent Claim
94 words
A method comprising: receiving a spread spectrum signal in an antenna array having a plurality of elements to produce spread spectrum signals respectively in the elements; frequency offsetting the spread spectrum signals in each array element from spread spectrum signals in the other array elements; summing the frequency offset signals to form a broadband composite signal of spread spectrum signals separated from one another by the frequency offsets; and despreading the spread spectrum signals of the broadband composite signal to form a first narrowband composite signal having narrowband signals separated by the frequency offset.
Claim 21
Dependent Claim
25 words
A method as in claim 18, further comprising down-converting the frequency of the narrowband signals in the narrowband composite signal in a receiver after despreading.
Claim 22
Dependent Claim
31 words
A method as in claim 18, wherein the despreading step comprises mixing the spread spectrum signals in the composite broadband signal with a local oscillator signal modulated by a despreading signal.
Claim 23
Dependent Claim
30 words
A method as in claim 20, wherein the spread spectrum signal includes a PN sequence code, and the despreading signal utilizes this PN sequence code to produce the narrowband signals.
Claim 24
Dependent Claim
19 words
A method as in claim 21, wherein the PN sequence code is a fast code sequence C f (t).
Claim 25
Dependent Claim
30 words
A method as in claim 18, wherein the frequency offsetting is provided by mixing the spread spectrum signals with frequency signals F 1 . . . F n , respectively.
Claim 26
Dependent Claim
17 words
A method as in claim 19, further comprising removing the frequency offset after processing in the receiver.
Claim 27
Dependent Claim
40 words
A method as in claim 24, wherein removing the frequency offset includes mixing the receiver output in a plurality of mixers MR 1 . . . MR n with frequency signals F 1 . . . F n , respectively.
Claim 28
Dependent Claim
32 words
A method as in claim 19, wherein the spread spectrum signal includes a PN fast code signal C f (t), and said method further includes error tracking the PN fast code alignment.
Claim 29
Dependent Claim
40 words
A method as in claim 26, wherein the error tracking includes multiplying the spread spectrum signals in the composite broadband signal by a despreading error function to produce a second composite narrowband signal for error tracking the PN fast code.
Claim 30
Dependent Claim
28 words
A method as in claim 19, wherein the despreading error function is: p(t)[C.sub.f (t+τ.sub.c)-C.sub.f (t-τ.sub.c)] where p(t) is a perturbational sequence and τ c is the chip time.
Claim 31
Dependent Claim
31 words
A method as in claim 27 or 28, wherein the error tracking further includes demodulating the receiver output to generate a misalignment PN error signal based on the despreading error function.
Claim 32
Dependent Claim
23 words
A method as in claim 18, wherein the spread spectrum signals includes a PN slow coding sequence C f (t) for beam steering.
Claim 33
Dependent Claim
30 words
A method as in claim 30, wherein the PN slow coding sequence has a frequency of at least twice the frequency of a data rate of the spread spectrum signals.
Claim 34
Dependent Claim
23 words
A method as in claim 18, wherein the spread spectrum signal includes a chirp signal, and the despreading signal includes a dechirp signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |