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US4918707A Expired / Lapsed US ⏱️ 0.0 years remaining

Spread spectrum demodulating device for spread spectrum communication system

Assignee: NEC Corp
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Filing: 1988-12-08
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Granted: 1990-04-17
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Expires: 2008-12-08
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Abstract

Abstract A spread spectrum demodulating device applicable to a spread spectrum communications system for demodulating a spread spectrum signal by inverse spread. A spread clock is directly recovered from a received spread spectrum signal to thereby generate a predetermined PN (Pseudo Noise) signal.

Inventors

  • 👤 Masashi Yoshihara

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 23:44
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/7073; H04B1/7075

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 212 words
A spread spectrum demodulating device for a spread spectrum communication system, comprising: splitter means for splitting into two a spread spectrum signal produced by spreading a PSK (Phase Shift Keying) modulated data signal by a PN (Pseudo Noise) signal; delay means for delaying one of two outputs of said splitter means by half a bit; first mixer means supplied at one input terminal with the one output of said splitter means and at the other input terminal with an output of said delay means for recovering a spread clock out of the spread spectrum signal; first band-pass filter means for filtering an output of said first mixer means to separate the recovered spread clock; phase shifter means for adjusting the separated recovered clock with respect to phase; AND gate means for gating an output of said phase shifter means in response to a sweep control signal which is entered from outside; PN generator means for generating the PN signal in response to the recovered spread clock which is fed from said AND gate means; second mixer means for inversely spreading the other output of said splitter means by an output of said PN generator means; and second band-pass filter means for removing unnecessary waves from an output of said second mixer means.
Claim 2
Dependent Claim 212 words
A spread spectrum demodulating device for a spread spectrum communication system, comprising: splitter means for splitting into two a spread spectrum signal produced by spreading a PSK (Phase Shift Keying) modulated data signal by a PN (Pseudo Noise) signal; delay means for delaying one of two outputs of said splitter means by half a bit; first mixer means supplied at one input terminal with the one output of said splitter means and at the other input terminal with an output of said delay means for recovering a spread clock out of the spread spectrum signal; first band-pass filter means for filtering an output of said first mixer means to separate the recovered spread clock; phase shifter means for adjusting the separated recovered clock with respect to phase; AND gate means for gating an output of said phase shifter means in response to a sweep control signal which is entered from outside; PN generator means for generating the PN signal in response to the recovered spread clock which is fed from said AND gate means; second mixer means for inversely spreading the other output of said splitter means by an output of said PN generator means; and second band-pass filter means for removing unnecessary waves from an output of said second mixer means.
Claim 3
Dependent Claim 47 words
A device as claimed in claim 1, wherein an output of said second band-pass filter means is fed to a PSK demodulating device which demodulates the data signal, said PSK demodulating device being monitored by controller means to see if said PSK demodulating device is operating correctly.
Claim 4
Dependent Claim 18 words
A device as claimed in claim 2, wherein the sweep control signal is fed from said controller means.

References Cited (Backward Citations)

US4017798A Cited
US4163944A Cited
US4285060A Cited
US4538280A Cited
US4635274A Cited
US4760586A Cited
US4761796A Cited
US4860307A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-04-16 1993-10-16 1994-04-17 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-04-16 1997-10-16 1998-04-17 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-04-16 2001-10-16 2002-04-17 $7700.00 Window Closed / Lapsed

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