Patent US5762625A successfully refreshed from Google Patents.
US4285060A
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Spread spectrum code tracking loop
Assignee: Harris Corp
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Filing: 1978-02-28
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Granted: 1981-08-18
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Expires: 1998-02-28
Abstract
Abstract A code tracking loop for a spread spectrum receiver includes a pair of mixer circuits to which phase offset or relatively delayed pseudo noise code signals are applied and combined with an incoming IF spread spectrum signal. The output of the mixers are coupled to a sum and difference hybrid. The hybrid produces a sum signal corresponding to the sum of the mixer outputs and a difference signal corresponding to the difference between the mixer outputs. These sum and difference signals are separately filtered, amplified and then coupled to a further mixer or phase detector. Appropriate AGC circuitry is controlled by the envelope of the sum signal to adjust the gains of the respective amplifiers. The output of the phase detector is proportional to the difference between the squares of the outputs of the hybrid and represents the phase of the sum signal relative to the difference signal. This phase-representative signal is coupled through a tracking loop filter to control the voltage controlled clock for the local PN code generator. A significant advantage of the inventive system is that even if the gains of the separate channels are not equal, this gain difference does not erroneously affect the output of the phase detector.
Inventors
- 👤 Raymond F. Cobb
- 👤 M. Guy Pelchat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:09
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/7073; H04B1/7085
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
114 words
A code timing recovery system for a spreadspectrum receiver comprising: first means for combining a received spreadspectrum signal containing a transmitted random sequence of pulses with first and second locally generated random sequences of pulses having a prescribed phase difference therebetween, to thereby produce first and second output signals representative of correlations of the random sequence of pulses contained in said received spread-spectrum signal with said first and second locally generated random sequences of pulses, respectively, and second means, coupled to said first means, for controlling the timing of said first and second locally generated random sequence of pulses in accordance with the difference between the squares of said first and second output signals.
Claim 2
Dependent Claim
114 words
A code timing recovery system for a spreadspectrum receiver comprising: first means for combining a received spreadspectrum signal containing a transmitted random sequence of pulses with first and second locally generated random sequences of pulses having a prescribed phase difference therebetween, to thereby produce first and second output signals representative of correlations of the random sequence of pulses contained in said received spread-spectrum signal with said first and second locally generated random sequences of pulses, respectively, and second means, coupled to said first means, for controlling the timing of said first and second locally generated random sequence of pulses in accordance with the difference between the squares of said first and second output signals.
Claim 3
Dependent Claim
117 words
In a code timing recovery system for a spread-spectrum receiver wherein a pair of phase displaced, locally generated random signal sequences are correlated with a random signal sequence contained in a transmitted spread-spectrum signal, to obtain first and second correlation signals, and said first and second correlation signals are coupled through first and second amplifier channels to a signal combining circuit for deriving a control signal by which the timing of said pair of locally generated random signal sequences relative to the random signal sequence contained in the transmitted spread-spectrum signal is controlled, the improvement wherein the timing control imparted by said derived control signal is independent of the gains of said first and second amplifier channels.
Claim 4
Dependent Claim
117 words
In a code timing recovery system for a spread-spectrum receiver wherein a pair of phase displaced, locally generated random signal sequences are correlated with a random signal sequence contained in a transmitted spread-spectrum signal, to obtain first and second correlation signals, and said first and second correlation signals are coupled through first and second amplifier channels to a signal combining circuit for deriving a control signal by which the timing of said pair of locally generated random signal sequences relative to the random signal sequence contained in the transmitted spread-spectrum signal is controlled, the improvement wherein the timing control imparted by said derived control signal is independent of the gains of said first and second amplifier channels.
Claim 5
Dependent Claim
115 words
In a code timing recovery system for a spread-spectrum receiver wherein a pair of phase displaced, locally generated random signal sequences are correlated with a random signal sequence contained in a transmitted spread-spectrum signal to obtain first and second correlation signals, and said first and second correlation signals are coupled through first and second amplifier channels and combined to provide a control signal by which the timing of said pair of locally generated random signal sequences relative to the random signal sequence contained in the transmitted spread-spectrum signal is adjusted, the improvement comprising the step of generating said control signal to adjust said timing independent of the gains of said first and second amplifier channels.
Claim 6
Dependent Claim
115 words
In a code timing recovery system for a spread-spectrum receiver wherein a pair of phase displaced, locally generated random signal sequences are correlated with a random signal sequence contained in a transmitted spread-spectrum signal to obtain first and second correlation signals, and said first and second correlation signals are coupled through first and second amplifier channels and combined to provide a control signal by which the timing of said pair of locally generated random signal sequences relative to the random signal sequence contained in the transmitted spread-spectrum signal is adjusted, the improvement comprising the step of generating said control signal to adjust said timing independent of the gains of said first and second amplifier channels.
Claim 7
Dependent Claim
155 words
A code timing recovery system for a spreadspectrum receiver comprising: first means for combining a received spreadspectrum signal containing a transmitted random signal sequence with first and second locally generated random signal sequences having a prescribed phase difference therebetween to thereby produce first and second output signals representative of correlations of the random signal sequence contained in said received spread-spectrum signal with said first and second locally generated random signal sequences, respectively, second means, coupled to said first means, for generating a pair of third and fourth output signals respectively representative of the sum of and difference between said first and second output signals, respectively, third means, coupled to said second means, for combining said third and fourth output signals to produce a fifth output signal; and fourth means, coupled to said third means, for controlling the timing of said first and second locally generated random signal sequences in accordance with said fifth output signal.
Claim 8
Dependent Claim
155 words
A code timing recovery system for a spreadspectrum receiver comprising: first means for combining a received spreadspectrum signal containing a transmitted random signal sequence with first and second locally generated random signal sequences having a prescribed phase difference therebetween to thereby produce first and second output signals representative of correlations of the random signal sequence contained in said received spread-spectrum signal with said first and second locally generated random signal sequences, respectively, second means, coupled to said first means, for generating a pair of third and fourth output signals respectively representative of the sum of and difference between said first and second output signals, respectively, third means, coupled to said second means, for combining said third and fourth output signals to produce a fifth output signal; and fourth means, coupled to said third means, for controlling the timing of said first and second locally generated random signal sequences in accordance with said fifth output signal.
Claim 9
Dependent Claim
33 words
A code timing recovery system according to claim 4, wherein said third means comprises means for producing said fifth output signal in accordance with the product of said third and fourth output signals.
Claim 10
Dependent Claim
29 words
A code timing recovery system according to claim 4, further including fifth means, coupled between said second and third means, for respectively amplifying said third and fourth output signals.
Claim 11
Dependent Claim
29 words
A code timing recovery system according to claim 5, further including fifth means, coupled between said second and third means, for respectively amplifying said third and fourth output signals.
Claim 12
Dependent Claim
31 words
A code timing recovery system according to claim 6, further including sixth means for controlling the amplification of said third and fourth output signals in accordance with said third output signal.
Claim 13
Dependent Claim
31 words
A code timing recovery system according to claim 7, further including sixth means for controlling the amplification of said third and fourth output signals in accordance with said third output signal.
Claim 14
Independent Claim
131 words
A method for controlling the timing of a locally generated code in a spread-spectrum receiver comprising the steps of: combining a received spread-spectrum signal containing a transmitted random signal sequence with first and second locally generated random signal sequences having a prescribed phase difference therebetween to thereby produce first and second signals representative of correlations of the random signal sequence contained in said received spread-spectrum signal with said first and second locally generated random signal sequences, respectively, generating a pair of third and fourth signals respectively representative of the sum of and difference between said first and second signals, respectively, combining said third and fourth signals to produce a fifth signal; and controlling the timing of said first and second locally generated random signal sequences in accordance with said fifth signal.
Claim 15
Independent Claim
131 words
A method for controlling the timing of a locally generated code in a spread-spectrum receiver comprising the steps of: combining a received spread-spectrum signal containing a transmitted random signal sequence with first and second locally generated random signal sequences having a prescribed phase difference therebetween to thereby produce first and second signals representative of correlations of the random signal sequence contained in said received spread-spectrum signal with said first and second locally generated random signal sequences, respectively, generating a pair of third and fourth signals respectively representative of the sum of and difference between said first and second signals, respectively, combining said third and fourth signals to produce a fifth signal; and controlling the timing of said first and second locally generated random signal sequences in accordance with said fifth signal.
Claim 16
Dependent Claim
26 words
A method according to claim 10, wherein said combining step comprises producing said fifth signal in accordance with the product of said third and fourth signals.
Claim 17
Dependent Claim
18 words
A method according to claim 10, further including the step of respectively amplifying said third and fourth signals.
Claim 18
Dependent Claim
18 words
A method according to claim 11, further including the step of respectively amplifying said third and fourth signals.
Claim 19
Dependent Claim
26 words
A method according to claim 12, further including the step of controlling the amplification of said third and fourth signals in accordance with said third signal.
Claim 20
Dependent Claim
26 words
A method according to claim 13, further including the step of controlling the amplification of said third and fourth signals in accordance with said third 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) | 1984-08-17 | 1985-02-16 | 1985-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-17 | 1989-02-16 | 1989-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-17 | 1993-02-16 | 1993-08-18 | $7700.00 | Window Closed / Lapsed |