US4581586A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crosstalk reduction in unbalanced QPSK detectors
Assignee: Lanteris Space LLC
•
Filing: 1984-08-17
•
Granted: 1986-04-08
•
Expires: 2004-08-17
Abstract
Abstract A method and apparatus for demodulating quadrature phase shift keyed (QPSK) signals in a manner which reduces crosstalk between channels. The in phase (I) data is recovered first by recovering the carrier frequency and then multiplying the carrier frequency by the QPSK signal. The I channel is contemplated to require higher power and thus the crosstalk error in the recovered I channel data is relatively small. The QPSK signal is then modulated with the recovered I channel data. The resulting signal is multiplied by a carrier in quadrature to the recovered carrier to produce a second signal in which the crosstalk component has been eliminated and which contains the quadrature (Q) channel data with the I channel modulation. The I channel modulation is removed by modulating the signal again by the I channel data to produce a signal containing only the Q channel data.
Inventors
- 👤 Michael D. Rubin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:16
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/02; H04L5/12; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
106 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; modulating the received signal with the recovered in phase data to produce a first signal; producing the quadrature carrier which is in quadrature to the carrier frequency; multiplying the first signal by the quadrature carrier to produce a second signal; and modulating the second signal with the received in phase data to produce the quadrature phase data.
Claim 2
Independent Claim
106 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; modulating the received signal with the recovered in phase data to produce a first signal; producing the quadrature carrier which is in quadrature to the carrier frequency; multiplying the first signal by the quadrature carrier to produce a second signal; and modulating the second signal with the received in phase data to produce the quadrature phase data.
Claim 3
Dependent Claim
25 words
A method as recited in claim 1 further comprising: synchronizing the in phase data before modulating the received signal and before modulating the second signal.
Claim 4
Dependent Claim
38 words
A method as recited in claim 2 further comprising: delaying the received signal before modulating it by the in phase data by an amount of time equal to the delay of the in phase data caused by synchronization.
Claim 5
Dependent Claim
18 words
A method as recited in claim 3 wherein the quadrature carrier is produced from the delayed received signal.
Claim 6
Dependent Claim
14 words
A method as recited in claim 1 further comprising: synchronizing the quadrature phase data.
Claim 7
Dependent Claim
20 words
A method as recited in claim 1 further including the step of filtering out the harmonics of the carrier frequency.
Claim 8
Independent Claim
121 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; synchronizing the in phase data; delaying the received signal; modulating the delayed received signal with the synchronized in phase data to produce a first signal; producing the quadrature carrier from the delayed received signal which is in quadrature to the carrier frequency; multiplying the first signal by the quadrature carrier to produce a second signal; and modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
Claim 9
Independent Claim
121 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; synchronizing the in phase data; delaying the received signal; modulating the delayed received signal with the synchronized in phase data to produce a first signal; producing the quadrature carrier from the delayed received signal which is in quadrature to the carrier frequency; multiplying the first signal by the quadrature carrier to produce a second signal; and modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
Claim 10
Independent Claim
116 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; producing the quadrature carrier from a representation of the received signal, such that the quadrature carrier is in quadrature phase relationship to the carrier frequency; modulating the quadrature carrier with the recovered in phase data to produce a first signal; multiplying the first signal by the representation of the received signal to produce a second signal; and modulating the second signal with the received in phase data.
Claim 11
Independent Claim
116 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; producing the quadrature carrier from a representation of the received signal, such that the quadrature carrier is in quadrature phase relationship to the carrier frequency; modulating the quadrature carrier with the recovered in phase data to produce a first signal; multiplying the first signal by the representation of the received signal to produce a second signal; and modulating the second signal with the received in phase data.
Claim 12
Dependent Claim
25 words
A method as recited in claim 8 further comprising: synchronizing the in phase data before modulating the quadrature carrier and before modulating the second signal.
Claim 13
Dependent Claim
38 words
A method as recited in claim 9 further comprising: delaying the representation of the received signal to produce the quadrature carrier by an amount of time equal to the delay of the in phase data caused by synchronization.
Claim 14
Dependent Claim
14 words
A method as recited in claim 8 further comprising: synchronizing the quadrature phase data.
Claim 15
Dependent Claim
20 words
A method as recited in claim 8 further including the step of filtering out the harmonics of the carrier frequency.
Claim 16
Independent Claim
114 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; synchronizing the in phase data; delaying the received signal; producing the quadrature carrier which is in quadrature to the carrier frequency from the delayed received signal; modulating the quadrature carrier with the synchronized in phase data to produce a first signal; multiplying the first signal by the delayed signal to produce a second signal; and modulating the second signal with the synchronized in phase data.
Claim 17
Independent Claim
114 words
A method of demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: recovering the carrier frequency from the received signal; recovering the in phase data by multiplying the received signal by the carrier frequency; synchronizing the in phase data; delaying the received signal; producing the quadrature carrier which is in quadrature to the carrier frequency from the delayed received signal; modulating the quadrature carrier with the synchronized in phase data to produce a first signal; multiplying the first signal by the delayed signal to produce a second signal; and modulating the second signal with the synchronized in phase data.
Claim 18
Independent Claim
118 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for modulating the received signal with the recovered in phase data to produce a first signal; means for producing the quadrature carrier which is in quadrature to the carrier frequency; means for multiplying the first signal by the quadrature carrier to produce a second signal; and means for modulating the second signal with the recovered in phase data to produce the quadrature phase data.
Claim 19
Independent Claim
118 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for modulating the received signal with the recovered in phase data to produce a first signal; means for producing the quadrature carrier which is in quadrature to the carrier frequency; means for multiplying the first signal by the quadrature carrier to produce a second signal; and means for modulating the second signal with the recovered in phase data to produce the quadrature phase data.
Claim 20
Dependent Claim
27 words
An apparatus as recited in claim 14 further comprising: means for synchronizing the in phase data before modulating the received signal and before modulating the second signal.
Claim 21
Dependent Claim
40 words
An apparatus as recited in claim 15 further comprising: means for delaying the received signal before modulating it by the in phase data by an amount of time equal to the delay of the in phase data caused by synchronization.
Claim 22
Dependent Claim
18 words
An apparatus as recited in claim 16 wherein the quadrature carrier is produced from the delayed received signal.
Claim 23
Dependent Claim
16 words
An apparatus as recited in claim 14 further comprising: means for synchronizing the quadrature phase data.
Claim 24
Dependent Claim
19 words
An apparatus as recited in claim 14 further including means for filtering out the harmonics of the carrier frequency.
Claim 25
Independent Claim
137 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for synchronizing the in phase data; means for delaying the received signal; means for modulating the delayed received signal with the synchronized in phase data to produce a first signal; means for producing the quadrature carrier which is in quadrature to the carrier frequency from the delayed received signal; means for multiplying the first signal by the quadrature carrier to produce a second signal; and means for modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
Claim 26
Independent Claim
137 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for synchronizing the in phase data; means for delaying the received signal; means for modulating the delayed received signal with the synchronized in phase data to produce a first signal; means for producing the quadrature carrier which is in quadrature to the carrier frequency from the delayed received signal; means for multiplying the first signal by the quadrature carrier to produce a second signal; and means for modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
Claim 27
Independent Claim
132 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for producing the quadrature carrier from a representation of the received signal such that the quadrature carrier is in quadrature to the carrier frequency; means for modulating the quadrature carrier with the recovered in phase data to produce a first signal; means for multiplying the first signal by the representation of the received signal to produce a second signal; and means for modulating the second signal with the recovered in phase data to produce the quadrature phase data.
Claim 28
Independent Claim
132 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for producing the quadrature carrier from a representation of the received signal such that the quadrature carrier is in quadrature to the carrier frequency; means for modulating the quadrature carrier with the recovered in phase data to produce a first signal; means for multiplying the first signal by the representation of the received signal to produce a second signal; and means for modulating the second signal with the recovered in phase data to produce the quadrature phase data.
Claim 29
Dependent Claim
27 words
An apparatus as recited in claim 21 further comprising: means for synchronizing the in phase data before modulating the quadrature carrier and before modulating the second signal.
Claim 30
Dependent Claim
40 words
An apparatus as recited in claim 22 further comprising: means for delaying the representation of the received signal to produce the quadrature carrier by an amount of time equal to the delay of the in phase data caused by synchronization.
Claim 31
Dependent Claim
16 words
An apparatus as recited in claim 21 further comprising: means for synchronizing the quadrature phase data.
Claim 32
Dependent Claim
19 words
An apparatus as recited in claim 21 further including means for filtering out the harmonics of the carrier frequency.
Claim 33
Independent Claim
137 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for synchronizing the in phase data; means for delaying the received signal; means for producing the quadrature carrier from the delayed received signal which is in quadrature to the carrier frequency; means for modulating the quadrature carrier with the synchronized in phase data to produce a first signal; means for multiplying the first signal by the delayed received signal to produce a second signal; and means for modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
Claim 34
Independent Claim
137 words
An apparatus for demodulating a received quadrature phase shift keyed signal, which includes a carrier frequency, in phase data, a quadrature carrier frequency and quadrature data, comprising: means for recovering the carrier frequency from the received signal; means for recovering the in phase data by multiplying the received signal by the carrier frequency; means for synchronizing the in phase data; means for delaying the received signal; means for producing the quadrature carrier from the delayed received signal which is in quadrature to the carrier frequency; means for modulating the quadrature carrier with the synchronized in phase data to produce a first signal; means for multiplying the first signal by the delayed received signal to produce a second signal; and means for modulating the second signal with the synchronized in phase data to produce the quadrature phase data.
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) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |