EP0373405A2
Expired / Lapsed
EP
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Automatic frequency control in the presence of data
Assignee: Motorola Solutions Inc
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Filing: 1989-12-11
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Granted: —
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Expires: 2009-12-11
Abstract
Abstract There is provided a method of and apparatus for Automatic Frequency Control (AFC) in the presence of data. It comprises removing the effects of data modulated onto the carrier (25), detecting the frequency difference between the carrier frequency and the phase of the reference oscillator (30), and adjusting (80) the frequency of the reference oscillator (35) to eliminate the frequency difference (Δ). It is further characterized by digitizing (40) the modulated carrier in quadrature, sampling (20) the modulated carrier in quadrature at a multiple of the modulated bit rate, rotating phases toward arctangent (I/Q)=0 (25/55/60) to remove the effects of quadrature data (I/Q) modulated onto the carrier, detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35) with a phase trajectory estimator (45), and establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35) with the phase trajectory estimator (45).
Inventors
- 👤 David Edward Borth
- 👤 James Frank Michael Kepler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:53
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2271; H04L27/2273; H04L27/0014; H04L2027/0024; H04L2027/0026; H04L2027/0038; H04L2027/0042; H04L2027/0044; H04L2027/0046; H04L2027/0051
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
57 words
A method of Automatic Frequency Control (AFC) in the presence of data characterized by: removing the effects of data modulated onto the carrier (25), detecting (30) the frequency difference between the carrier frequency and the frequency of the reference oscillator (35), and adjusting (80) the frequency of the reference oscillator (35) to eliminate the frequency difference (Δ).
Claim 2
Independent Claim
57 words
A method of Automatic Frequency Control (AFC) in the presence of data characterized by: removing the effects of data modulated onto the carrier (25), detecting (30) the frequency difference between the carrier frequency and the frequency of the reference oscillator (35), and adjusting (80) the frequency of the reference oscillator (35) to eliminate the frequency difference (Δ).
Claim 3
Dependent Claim
28 words
A method is claimed in Claim 1, wherein the effects of data modulated onto the carrier are removed by rotating (60) phases toward a point of coincidence (25/55/60).
Claim 4
Dependent Claim
28 words
A method is claimed in Claim 1, wherein the effects of quadrature data (I/Q) modulated onto the carrier are removed by rotating (60) phases toward arctangent (55) (I/Q)=0.
Claim 5
Dependent Claim
27 words
A method is claimed in Claim 2, wherein the time rate of change of the phase rotation (45) is the frequency adjustment required for the reference oscillator.
Claim 6
Dependent Claim
20 words
A method is claimed in Claim 3, wherein the difference from zero is determined with a phase trajectory estimator (45).
Claim 7
Dependent Claim
36 words
A method is claimed in Claim 5, wherein the phase trajectory estimator (45) is further employed to establish and generate (80) the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35).
Claim 8
Dependent Claim
16 words
A method is claimed in Claim 1, wherein the data is GMSK phase-modulated onto the carrier.
Claim 9
Dependent Claim
29 words
A method is claimed in Claim 2, wherein phase rotation (25) is preceded by sampling the modulated carrier in quadrature at a multiple of the modulated bit rate (20).
Claim 10
Dependent Claim
20 words
A method is claimed in Claim 8, wherein sampling (20) is preceded by digitizing (40) the modulated carrier in quadrature.
Claim 11
Independent Claim
86 words
A method of Automatic Frequency Control (AFC) in the presence of phase-modulated data characterized by: rotating (60) phases toward a point of coincidence (25/55/60) to remove the effects of data modulated onto the carrier, detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35) with a phase trajectory estimator (45), establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35) with the phase trajectory estimator (45).
Claim 12
Independent Claim
86 words
A method of Automatic Frequency Control (AFC) in the presence of phase-modulated data characterized by: rotating (60) phases toward a point of coincidence (25/55/60) to remove the effects of data modulated onto the carrier, detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35) with a phase trajectory estimator (45), establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35) with the phase trajectory estimator (45).
Claim 13
Independent Claim
103 words
A method of Automatic Frequency Control (AFC) in the presence of GMSK phase-modulated data characterized by: digitizing (40) the quadrature-modulated carrier, sampling (20) the quadrature-modulated carrier at a multiple of the modulated bit rate, rotating phases toward arctangent (I/Q)=0 to remove the effects of quadrature data (I/Q) modulated onto the carrier (25), detecting (30) the frequency difference between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35) with a phase trajectory estimator (45), establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35) with the phase trajectory estimator (45).
Claim 14
Independent Claim
103 words
A method of Automatic Frequency Control (AFC) in the presence of GMSK phase-modulated data characterized by: digitizing (40) the quadrature-modulated carrier, sampling (20) the quadrature-modulated carrier at a multiple of the modulated bit rate, rotating phases toward arctangent (I/Q)=0 to remove the effects of quadrature data (I/Q) modulated onto the carrier (25), detecting (30) the frequency difference between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35) with a phase trajectory estimator (45), establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35) with the phase trajectory estimator (45).
Claim 15
Independent Claim
66 words
An apparatus for Automatic Frequency Control (AFC) in the presence of data characterized by, coupled in series: means for removing the effects of data modulated onto the carrier (25) and means for detecting (30) the frequency difference (Δ) between the carrier frequency and the phase of the reference oscillator (35) and for adjusting (80) the frequency of the reference oscillator (35) by the frequency difference (Δ).
Claim 16
Independent Claim
66 words
An apparatus for Automatic Frequency Control (AFC) in the presence of data characterized by, coupled in series: means for removing the effects of data modulated onto the carrier (25) and means for detecting (30) the frequency difference (Δ) between the carrier frequency and the phase of the reference oscillator (35) and for adjusting (80) the frequency of the reference oscillator (35) by the frequency difference (Δ).
Claim 17
Independent Claim
82 words
An apparatus for Automatic Frequency Control (AFC) in the presence of phase-modulated data characterized by, coupled in series: means for rotating phases toward a point of coincidence to remove the effects of data modulated onto the carrier (25), means for detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35), and for establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35).
Claim 18
Independent Claim
82 words
An apparatus for Automatic Frequency Control (AFC) in the presence of phase-modulated data characterized by, coupled in series: means for rotating phases toward a point of coincidence to remove the effects of data modulated onto the carrier (25), means for detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35), and for establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35).
Claim 19
Independent Claim
105 words
An apparatus for Automatic Frequency Control (AFC) in the presence of GMSK phase-modulated data characterized by, coupled in series: means for digitizing the quadrature-modulated carrier (40), means for sampling the quadrature-modulated carrier at a multiple of the modulated bit rate (20), means for rotating phases toward arctangent (I/Q)=0 to remove the effects of quadrature data (I/Q) modulated onto the carrier (25), means for detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35), and for establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35).
Claim 20
Independent Claim
105 words
An apparatus for Automatic Frequency Control (AFC) in the presence of GMSK phase-modulated data characterized by, coupled in series: means for digitizing the quadrature-modulated carrier (40), means for sampling the quadrature-modulated carrier at a multiple of the modulated bit rate (20), means for rotating phases toward arctangent (I/Q)=0 to remove the effects of quadrature data (I/Q) modulated onto the carrier (25), means for detecting (30) the frequency difference (Δ) between the carrier frequency and the frequency of a Voltage Controlled type of reference oscillator (35), and for establishing and generating the requisite correction voltage (Δ) for a Voltage Controlled type of reference oscillator (VCO) (35).
References Cited (Backward Citations)
No citation records indexed.
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