US5469112A
Expired / Lapsed
US
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Communication device with zero-crossing demodulator
Assignee: Motorola Solutions Inc
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Filing: 1994-08-15
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Granted: 1995-11-21
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Expires: 2014-08-15
Abstract
Abstract A communication device (100) includes mixers (104) and (108) which mix a local oscillator (112, 106) with a received signal to produce in-phase (i) and quadrature (q) components. The direction of the phase of the signal is detected as it crosses the i and q axes. The direction of the phase rotation is kept track of by a bi-directional counter (123) in order to demodulate multi-level digital signals. A positive rotation increments the bi-directional counter (123). Conversely, a negative direction decrements the counter (123). The final count of the counter (123) is used by a decision device 124 to establish the content of the received information signal.
Inventors
- 👤 Edward K. B. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:11
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/10; H04L27/14; H04L27/156; H04L27/1563
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
92 words
A communication device for receiving an information signal, comprising: a first mixer for producing a first in-phase component; a second mixer for producing a first quadrature phase component; a multi-level detector for detecting the contents of the information signal using the in-phase and quadrature components, the detector comprising: means for detecting the direction of instantaneous phase rotation at zero crossings; a bi-directional counter for incrementing when a positive direction is detected and decrementing when a negative direction is detected; and means for extrapolating the contents of the information signal from the counter.
Claim 2
Dependent Claim
92 words
A communication device for receiving an information signal, comprising: a first mixer for producing a first in-phase component; a second mixer for producing a first quadrature phase component; a multi-level detector for detecting the contents of the information signal using the in-phase and quadrature components, the detector comprising: means for detecting the direction of instantaneous phase rotation at zero crossings; a bi-directional counter for incrementing when a positive direction is detected and decrementing when a negative direction is detected; and means for extrapolating the contents of the information signal from the counter.
Claim 3
Dependent Claim
36 words
The communication device of claim 1, further including means for manipulating the first in-phase and quadrature components to produce additional zero crossings by generating at least a second in-phase component and a second quadrature phase component.
Claim 4
Dependent Claim
34 words
The communication device of claim 2, wherein the means for detecting includes a zero crossing detector for detecting zero crossings using the first in-phase and quadrature components and the second in-phase and quadrature components.
Claim 5
Dependent Claim
16 words
The communication device of claim 2, wherein the means for manipulating includes at least one summer.
Claim 6
Dependent Claim
16 words
The communication device of claim 2, wherein the means for manipulating includes at least one subtractor.
Claim 7
Dependent Claim
22 words
The communication device of claim 1, further including first and second low pass filters coupled to the first and second mixers, respectively.
Claim 8
Dependent Claim
10 words
The communication device of claim 1, further including an antenna.
Claim 9
Dependent Claim
20 words
The communication device of claim 7, further including a coupler for coupling the antenna to the first and second mixers.
Claim 10
Dependent Claim
26 words
The communication device of claim 8, wherein the coupler includes a first frequency down converter to render the communication device a dual conversion zero IF device.
Claim 11
Independent Claim
77 words
A method for detecting the contents of an information signal, comprising the steps off generating an IF signal having in-phase and quadrature components; monitoring the phase rotation in order to detect zero crossings; establishing the instantaneous direction of the phase rotation at each of the zero crossings; combining all the instantaneous directions of the phase rotation to create an overall phase rotation angle; and estimating the contents of the information signal using the overall phase rotation angle.
Claim 12
Independent Claim
77 words
A method for detecting the contents of an information signal, comprising the steps off generating an IF signal having in-phase and quadrature components; monitoring the phase rotation in order to detect zero crossings; establishing the instantaneous direction of the phase rotation at each of the zero crossings; combining all the instantaneous directions of the phase rotation to create an overall phase rotation angle; and estimating the contents of the information signal using the overall phase rotation angle.
Claim 13
Dependent Claim
21 words
The method of claim 10, further including the step of manipulating the in-phase and quadrature components to produce additional zero crossings.
Claim 14
Dependent Claim
22 words
The method of claim 11, wherein the step of manipulating includes the step of adding the in-phase and quadrature phase components together.
Claim 15
Dependent Claim
24 words
The method of claim 11, wherein the step of manipulating includes the step of subtracting the in-phase and quadrature phase components from each other.
Claim 16
Independent Claim
85 words
A method for detecting the contents of an information signal, comprising the steps of: generating an IF signal having in-phase and quadrature components; monitoring the in-phase and quadrature components to determine instantaneous phase rotation direction at zero crossings; incrementing a bi-directional counter when a positive direction is detected and decrementing the counter when a negative direction is detected; estimating the overall phase rotation angle using the output of the bi-directional counter; and converting the phase rotation angle to detect the contents of the information signal.
Claim 17
Independent Claim
85 words
A method for detecting the contents of an information signal, comprising the steps of: generating an IF signal having in-phase and quadrature components; monitoring the in-phase and quadrature components to determine instantaneous phase rotation direction at zero crossings; incrementing a bi-directional counter when a positive direction is detected and decrementing the counter when a negative direction is detected; estimating the overall phase rotation angle using the output of the bi-directional counter; and converting the phase rotation angle to detect the contents of the information signal.
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) | 1998-11-20 | 1999-05-22 | 1999-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-11-20 | 2003-05-22 | 2003-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-11-20 | 2007-05-22 | 2007-11-21 | $7700.00 | Window Closed / Lapsed |