US4731801A
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Method for the reception and detection of digital signals
Assignee: Nokia Oyj
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Filing: 1985-11-05
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Granted: 1988-03-15
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Expires: 2005-11-05
Abstract
Abstract Described herein is a method for the reception and the detection of digital signals. According to the method at least two signals (s 1 , s 2 , . . . , s M ) having at least approximately the same information content are received and out of each received signal (S i ) is generated by means of a phase shift one in-phase baseband signal (s iI ) and one quadrature baseband signal (s iQ ). All in-phase baseband signals (s iI ) are summed in a first summing point (3a) and all quadrature baseband signals (s iQ ) in a second summing point (3b), both sum signals (y Ik and y Qk ) are fed to a detector (4) for detection and generating two detected output signals (s Ik and s Qk ), and a reference carrier (ca) is generated as a function of said two sum signals (y Ik and y Qk ) for carrying out a coherent demodulation. According to the invention a projection voltage (z k ) defined by the equation z k =y Qk s Ik -y Ik s.sub. Qk is generated, wherein y Ik is a signal sample in the in-phase branch before threshold decision in the detector, y Qk is the signal sample in the quadrature branch before decision, s Ik is the detected signal in the in-phase branch, and s Qk is the detected signal in the quadrature branch.
Inventors
- 👤 Jukka Henriksson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:09
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
327 words
A method for the reception and the detection of digital signals, comprising: receiving at least two signals (s 1 , s 2 , . . . , s M ) having at least approximately the same information content, by means of at least one antenna or equivalent, generating out of each received signal (s i ), by means of a phase shift, and a demodulation, one in-phase baseband signal (s iI ) and one quadrature baseband signal (s iQ ), summing all in-phase baseband signals (s iI ) in a first summing point and all quadrature baseband signals (s iQ ) in a second summing point, feeding both sum signals (y Ik and y Qk ) to a detector (4) for detection and generating two detected output signals (s Ik and s Qk ), and generating a reference carrier (ca) as a function of said two sum signals (y Ik and y Qk ) for carrying out a coherent demodulation, characterized by generating a projection voltage (z k ) defined by the following equation z.sub.k =y.sub.Qk s.sub.Ik -y.sub.Ik s.sub.Qk, wherein y Ik is a signal sample in the in-phase branch before threshold decision in the detector, y Qk is the signal sample in the quadrature branch before decision, s Ik is the detected signal in the in-phase branch, and s Qk is the detected signal in the quadrature branch, generating a product signal (b) by multiplying the projection voltage (z k ) with a signal (r) being a function of said sum signals (y Ik and y Qk ), generating control voltages (c 1 , . . . , c M ) by correlating said product signal (b) with each received signal (s 1 , . . . , s M ), by means of correlators (Cor 1 , . . . , Cor M ), and controlling the phase shifts by means of said control voltages (c 1 , . . . , c M ).
Claim 2
Independent Claim
327 words
A method for the reception and the detection of digital signals, comprising: receiving at least two signals (s 1 , s 2 , . . . , s M ) having at least approximately the same information content, by means of at least one antenna or equivalent, generating out of each received signal (s i ), by means of a phase shift, and a demodulation, one in-phase baseband signal (s iI ) and one quadrature baseband signal (s iQ ), summing all in-phase baseband signals (s iI ) in a first summing point and all quadrature baseband signals (s iQ ) in a second summing point, feeding both sum signals (y Ik and y Qk ) to a detector (4) for detection and generating two detected output signals (s Ik and s Qk ), and generating a reference carrier (ca) as a function of said two sum signals (y Ik and y Qk ) for carrying out a coherent demodulation, characterized by generating a projection voltage (z k ) defined by the following equation z.sub.k =y.sub.Qk s.sub.Ik -y.sub.Ik s.sub.Qk, wherein y Ik is a signal sample in the in-phase branch before threshold decision in the detector, y Qk is the signal sample in the quadrature branch before decision, s Ik is the detected signal in the in-phase branch, and s Qk is the detected signal in the quadrature branch, generating a product signal (b) by multiplying the projection voltage (z k ) with a signal (r) being a function of said sum signals (y Ik and y Qk ), generating control voltages (c 1 , . . . , c M ) by correlating said product signal (b) with each received signal (s 1 , . . . , s M ), by means of correlators (Cor 1 , . . . , Cor M ), and controlling the phase shifts by means of said control voltages (c 1 , . . . , c M ).
Claim 3
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the shift operation is carried out before the demodulation.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1, characterized in that the shift operation is carried out after the demodulation.
Claim 5
Dependent Claim
33 words
A method claimed in claim 1, characterized in that the signal being a function of the sum signals (y Ik and y Qk ) is a remodulated signal (r) of the sum signals.
Claim 6
Dependent Claim
29 words
A method as claimed in claim 2, characterized in that the signal correlated with the product signal (b) is a shifted but not yet demodulated signal (s' 1 ).
Claim 7
Dependent Claim
28 words
A method as claimed in claim 2, characterized in that the phase shift in the coherent demodulation is carried out by shifting the phase of the carrier (ca).
Claim 8
Dependent Claim
26 words
A method as claimed in claim 1, characterized in that angle modulation, e.g., 2-, 4-, . . . , n-phase modulation, is used as modulation method.
Claim 9
Dependent Claim
25 words
A method as claimed in claim 1, characterized in that combined angle and amplitude modulation, e.g., the QAM method, is used as a modulation method.
Claim 10
Dependent Claim
33 words
A method as claimed in claim 1, characterized in that all signals but one (s 1 , s 2 , . . . , s M-1 ) are subjected to the phase shift.
Claim 11
Dependent Claim
28 words
A method as claimed in claim 3, characterized in that the phase shift in the coherent demodulation is carried out by shifting the phase of the carrier (ca).
Claim 12
Independent Claim
338 words
A method for the reception and the detection of digital signals, comprising: receiving at least two signals (s 1 , s 2 , . . . , s M ) having at least approximately the same information content, by means of at least one antenna or equivalent, generating out of each received signal s i , by means of a phase shift, an amplitude shift, and a demodulation, one in-phase baseband signal (s iI ) and one quadrature baseband signal (s iQ ), summing all in-phase baseband signals (s iI ) in a first summing point and all quadrature baseband signals (s iQ ) in a second summing point, feeding both sum signals (Y IK and Y Qk ) to a detector (4) for detection and generting two detected output signals (s Ik and s Qk ), and generating a reference carrier (ca) as a function of said two sum signals (Y Ik and Y Qk ) for carrying out a coherent demodulation, characterized by generating a projection voltage (z k ) defined by the following equation z.sub.k =Y.sub.Qk s.sub.Ik -Y.sub.Ik s.sub.Qk, wherein Y Ik is a signal sample in the in-phase branch before threshold decision in the detector, Y Qk is the signal sample in the quadrature branch before decision, s Ik is the detected signal in the in-phase branch, and s Qk is the detected signal in the quadrature branch, generating a product signal (b) by multiplying the projection voltage (z k ) with a signal (r) being a function of said sum signals (Y Ik and Y Qk ), generating control voltages (c 1 , . . . , c M ) by correlating said product signal (b) with each received signal related to (s 1 , . . . , s M ) by means of correlators (Cor 1 , . . . , Cor M ), and controlling the phase shifts or the phase and amplitude shifts by means of said control voltages (c 1 , . . . , c M ).
Claim 13
Independent Claim
338 words
A method for the reception and the detection of digital signals, comprising: receiving at least two signals (s 1 , s 2 , . . . , s M ) having at least approximately the same information content, by means of at least one antenna or equivalent, generating out of each received signal s i , by means of a phase shift, an amplitude shift, and a demodulation, one in-phase baseband signal (s iI ) and one quadrature baseband signal (s iQ ), summing all in-phase baseband signals (s iI ) in a first summing point and all quadrature baseband signals (s iQ ) in a second summing point, feeding both sum signals (Y IK and Y Qk ) to a detector (4) for detection and generting two detected output signals (s Ik and s Qk ), and generating a reference carrier (ca) as a function of said two sum signals (Y Ik and Y Qk ) for carrying out a coherent demodulation, characterized by generating a projection voltage (z k ) defined by the following equation z.sub.k =Y.sub.Qk s.sub.Ik -Y.sub.Ik s.sub.Qk, wherein Y Ik is a signal sample in the in-phase branch before threshold decision in the detector, Y Qk is the signal sample in the quadrature branch before decision, s Ik is the detected signal in the in-phase branch, and s Qk is the detected signal in the quadrature branch, generating a product signal (b) by multiplying the projection voltage (z k ) with a signal (r) being a function of said sum signals (Y Ik and Y Qk ), generating control voltages (c 1 , . . . , c M ) by correlating said product signal (b) with each received signal related to (s 1 , . . . , s M ) by means of correlators (Cor 1 , . . . , Cor M ), and controlling the phase shifts or the phase and amplitude shifts by means of said control voltages (c 1 , . . . , c M ).
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) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |