US6236267B1
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US
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Linearization for power amplifiers using feed-forward and feedback control
Assignee: International Business Machines Corp
•
Filing: 1998-12-29
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Granted: 2001-05-22
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Expires: 2018-12-29
Abstract
Abstract The present invention is a method and apparatus for linearizing an output signal which is generated by a power amplifier (PA). A phase compensation on the output signal is performed using a phase feed-forward path and a phase feedback path. An amplitude compensation on the output signal is performed using an amplitude feed-forward path and an amplitude feedback path. The amplitude compensation is synchronized with the phase compensation.
Inventors
- 👤 Claudio Anzil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:40
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3247; H03C; H03C5/00; H03F1/3282; H03F2200/00; H03F2200/102; H03F2201/00; H03F2201/32; H03F2201/3233
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
60 words
A method comprising: (a) performing a phase compensation on an output signal generated by a power amplifier (PA) using a phase feed-forward path and a phase feedback path; (b) performing an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) synchronizing the phase compensation with the amplitude compensation based on time.
Claim 2
Independent Claim
60 words
A method comprising: (a) performing a phase compensation on an output signal generated by a power amplifier (PA) using a phase feed-forward path and a phase feedback path; (b) performing an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) synchronizing the phase compensation with the amplitude compensation based on time.
Claim 3
Dependent Claim
46 words
The method of claim 1 wherein performing a phase compensation comprises: (a1) generating a PA input signal based on control parameters in the phase feed-forward path; and (a2) updating the control parameters based on a result of a feedback phase comparison in the phase feedback path.
Claim 4
Dependent Claim
75 words
The method of claim 2 wherein generating a PA input signal comprises: generating a sequence of digital data representing a synthesized signal at a predetermined frequency by a direct digital synthesizer; converting the sequence of digital data into an analog signal by a phase digital-to-analog converter (DAC); generating an edge signal from the analog signal by a hard limiter; and phase locking the edge signal to generate the PA input signal by a phase-locked loop.
Claim 5
Dependent Claim
76 words
The method of claim 3 wherein phase locking comprises: down converting the PA input signal to a first phase signal by a first down converter; comparing the first phase signal with the edge signal to produce a first phase error signal by a first phase detector; integrating the first phase error signal to generate a control signal by an integrator; and generating the PA input signal based on the control signal by a voltage-controlled oscillator (VCO).
Claim 6
Dependent Claim
60 words
The method of claim 2 wherein updating the control parameters comprises: down converting the output signal to a second phase signal by a second down converter; comparing the second phase signal with the first phase signal to generate a second phase error signal by a second phase detector; and modifying the control parameters based on the second phase error signal.
Claim 7
Dependent Claim
17 words
The method of claim 2 wherein the control parameters are stored in a phase look-up table (LUT).
Claim 8
Dependent Claim
67 words
The method of claim 1 wherein performing an amplitude compensation comprises: (b1) adjusting a power level of the PA based on an amplitude control parameter in the amplitude feed-forward path; (b2) detecting an output amplitude of the output signal in the amplitude feedback path by an amplitude modulation (AM) detector; and (b3) comparing the detected output amplitude with a predetermined amplitude to generate the amplitude control parameter.
Claim 9
Dependent Claim
53 words
The method of claim 7 wherein adjusting a power level of the PA comprises: generating a power control data based on the amplitude control parameter; and converting the power control data to a power control signal by an amplitude digital-to-analog converter (DAC), the power control signal adjusting the power level of the PA.
Claim 10
Dependent Claim
18 words
The method of claim 7 wherein detecting an output amplitude includes detecting an envelope of the output signal.
Claim 11
Dependent Claim
15 words
The method of claim 7 wherein the predetermined amplitude is stored in an amplitude LUT.
Claim 12
Independent Claim
80 words
An apparatus comprising: (a) a phase compensator to perform a phase compensation on an output signal generated by a power amplifier (PA) using a phase feed-forward path and a phase feedback path; (b) an amplitude compensator to perform an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) a synchronizer coupled to the phase compensator and the amplitude compensator to synchronize the phase compensation and the amplitude compensation based on time.
Claim 13
Independent Claim
80 words
An apparatus comprising: (a) a phase compensator to perform a phase compensation on an output signal generated by a power amplifier (PA) using a phase feed-forward path and a phase feedback path; (b) an amplitude compensator to perform an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) a synchronizer coupled to the phase compensator and the amplitude compensator to synchronize the phase compensation and the amplitude compensation based on time.
Claim 14
Dependent Claim
61 words
The apparatus of claim 11 wherein the phase compensator comprises: (a1) a signal generator for generating a PA input signal based on control parameters in the phase feed-forward path; and (a2) a phase control parameter generator (PCPG) coupled to the signal generator for updating the control parameters based on a result of a feedback phase comparison in the phase feedback path.
Claim 15
Dependent Claim
88 words
The apparatus of claim 12 wherein the signal generator comprises: a direct digital synthesizer (DDS) for generating a sequence of digital data representing a synthesized signal at a predetermined frequency; a phase digital-to-analog converter (DAC) coupled to the DDS for converting the sequence of digital data into an analog signal; a hard limiter coupled to the phase DAC for generating an edge signal from the analog signal; and a phase-locked loop coupled to the hard limiter for phase locking the edge signal to generate the PA input signal.
Claim 16
Dependent Claim
93 words
The apparatus of claim 13 wherein the phase-locked loop comprises: a first down converter for down converting the PA input signal to a first phase signal; a first phase detector coupled to the first down converter for comparing the first phase signal with the edge signal to produce a first phase error signal; an integrator coupled to the first phase detector for integrating the first phase error signal to generate a control signal; and a voltage-controlled oscillator (VCO) coupled to the integrator for generating the PA input signal based on the control signal.
Claim 17
Dependent Claim
78 words
The apparatus of claim 12 wherein the phase feedback path comprises: a second down converter coupled to the PA for down converting the output signal to a second phase signal; a second phase detector coupled to the first and second down converters for comparing the second phase signal with the first phase signal to generate a second phase error signal; and wherein the phase control parameter generator modifies the control parameters based on the second phase error signal.
Claim 18
Dependent Claim
17 words
The apparatus of claim 12 wherein the control parameters are stored in a phase look-up table (LUT).
Claim 19
Dependent Claim
90 words
The apparatus of claim 11 wherein the amplitude compensator comprises: (b1) an amplitude DAC coupled to the PA for adjusting a power level of the PA based on an amplitude control parameter in the amplitude feed-forward path; (b2) an amplitude modulation (AM) detector coupled to the PA for detecting an output amplitude of the output signal in the amplitude feedback path; and (b3) an amplitude control parameter generator (ACPG) coupled to the AM detector for comparing the detected output amplitude with a predetermined amplitude to generate the amplitude control parameter.
Claim 20
Dependent Claim
85 words
The apparatus of claim 17 wherein the ACPG comprises: an amplitude parameter table for storing predetermined amplitude values; an amplitude converter for converting the detected output amplitude to an amplitude signal level compatible with the predetermined amplitude values; an amplitude comparator coupled to the amplitude parameter table and the amplitude converter for comparing the predetermined amplitude values and the converted amplitude signal, the amplitude comparator generating a control level; and an automatic level controller coupled to the amplitude comparator for generating a power control signal.
Claim 21
Dependent Claim
13 words
The apparatus of claim 17 wherein the AM detector includes an envelope detector.
Claim 22
Dependent Claim
15 words
The apparatus of claim 17 wherein the predetermined amplitude is stored in an amplitude LUT.
Claim 23
Dependent Claim
115 words
A communication system comprising: an antenna for transmitting an output signal; a power amplifier (PA) coupled to the antenna for generating the output signal; a linearizing circuit coupled to the PA to linearize the output signal generated by the PA, the linearizing circuit comprising: (a) a phase compensator to perform a phase compensation on the output signal using a phase feed-forward path and a phase feedback path; (b) an amplitude compensator to perform an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) a synchronizer coupled to the phase compensator and the amplitude compensator to synchronize the phase compensation and the amplitude compensation based on time.
Claim 24
Dependent Claim
115 words
A communication system comprising: an antenna for transmitting an output signal; a power amplifier (PA) coupled to the antenna for generating the output signal; a linearizing circuit coupled to the PA to linearize the output signal generated by the PA, the linearizing circuit comprising: (a) a phase compensator to perform a phase compensation on the output signal using a phase feed-forward path and a phase feedback path; (b) an amplitude compensator to perform an amplitude compensation on the output signal using an amplitude feed-forward path and an amplitude feedback path; and (c) a synchronizer coupled to the phase compensator and the amplitude compensator to synchronize the phase compensation and the amplitude compensation based on time.
Claim 25
Dependent Claim
62 words
The communication system of claim 21 wherein the phase compensator comprises: (a1) a signal generator for generating a PA input signal based on control parameters in the phase feed-forward path; and (a2) a phase control parameter generator (PCPG) coupled to the signal generator for updating the control parameters based on a result of a feedback phase comparison in the phase feedback path.
Claim 26
Dependent Claim
89 words
The communication system of claim 22 wherein the signal generator comprises: a direct digital synthesizer (DDS) for generating a sequence of digital data representing a synthesized signal at a predetermined frequency; a phase digital-to-analog converter (DAC) coupled to the DDS for converting the sequence of digital data into an analog signal; a hard limiter coupled to the phase DAC for generating an edge signal from the analog signal; and a phase-locked loop coupled to the hard limiter for phase locking the edge signal to generate the PA input signal.
Claim 27
Dependent Claim
94 words
The communication system of claim 23 wherein the phase-locked loop comprises: a first down converter for down converting the PA input signal to a first phase signal; a first phase detector coupled to the first down converter for comparing the first phase signal with the edge signal to produce a first phase error signal; an integrator coupled to the first phase detector for integrating the first phase error signal to generate a control signal; and a voltage-controlled oscillator (VCO) coupled to the integrator for generating the PA input signal based on the control signal.
Claim 28
Dependent Claim
79 words
The communication system of claim 22 wherein the phase feedback path comprises: a second down converter coupled to the PA for down converting the output signal to a second phase signal; a second phase detector coupled to the first and second down converters for comparing the second phase signal with the first phase signal to generate a second phase error signal; and wherein the phase control parameter generator modifies the control parameters based on the second phase error signal.
Claim 29
Dependent Claim
18 words
The communication system of claim 22 wherein the control parameters are stored in a phase look-up table (LUT).
Claim 30
Dependent Claim
91 words
The communication system of claim 21 wherein the amplitude compensator comprises: (b1) an amplitude DAC coupled to the PA for adjusting a power level of the PA based on an amplitude control parameter in the amplitude feed-forward path; (b2) an amplitude modulation (AM) detector coupled to the PA for detecting an output amplitude of the output signal in the amplitude feedback path; and (b3) an amplitude control parameter generator (ACPG) coupled to the AM detector for comparing the detected output amplitude with a predetermined amplitude to generate the amplitude control parameter.
Claim 31
Dependent Claim
86 words
The communication system of claim 27 wherein the ACPG comprises: an amplitude parameter table for storing predetermined amplitude values; an amplitude converter for converting the detected output amplitude to an amplitude signal level compatible with the predetermined amplitude values; an amplitude comparator coupled to the amplitude parameter table and the amplitude converter for comparing the predetermined amplitude values and the converted amplitude signal, the amplitude comparator generating a control level; and an automatic level controller coupled to the amplitude comparator for generating a power control signal.
Claim 32
Dependent Claim
14 words
The communication system of claim 27 wherein the AM detector includes an envelope detector.
Claim 33
Dependent Claim
16 words
The communication system of claim 27 wherein the predetermined amplitude is stored in an amplitude LUT.
Claim 34
Independent Claim
96 words
A method comprising: transmitting the output signal via an antenna; generating the output signal by a power amplifier (PA); linearizing the output signal generated by the PA by a linearizing circuit, the linearizing comprising: (a) performing a phase compensation on the output signal by a phase compensator using a phase feed-forward path and a phase feedback path; (b) performing an amplitude compensation on the output signal by an amplitude compensator using an amplitude feed-forward path and an amplitude feedback path; and (c) synchronizing the phase compensation and the amplitude compensation by a synchronizer based on time.
Claim 35
Independent Claim
96 words
A method comprising: transmitting the output signal via an antenna; generating the output signal by a power amplifier (PA); linearizing the output signal generated by the PA by a linearizing circuit, the linearizing comprising: (a) performing a phase compensation on the output signal by a phase compensator using a phase feed-forward path and a phase feedback path; (b) performing an amplitude compensation on the output signal by an amplitude compensator using an amplitude feed-forward path and an amplitude feedback path; and (c) synchronizing the phase compensation and the amplitude compensation by a synchronizer based on time.
Claim 36
Dependent Claim
57 words
The method of claim 31 wherein performing the phase compensation comprises: (a1) generating a PA input signal based on control parameters in the phase feed-forward path by a signal generator; and (a2) updating the control parameters based on a result of a feedback phase comparison in the phase feedback path by a phase control parameter generator (PCPG).
Claim 37
Dependent Claim
76 words
The method of claim 32 wherein generating a PA input signal comprises: generating a sequence of digital data representing a synthesized signal at a predetermined frequency by a direct digital synthesizer (DDS); converting the sequence of digital data into an analog signal by a phase digital-to-analog converter (DAC); generating an edge signal from the analog signal by a hard limiter; and phase locking the edge signal to generate the PA input signal by a phase-locked loop.
Claim 38
Dependent Claim
77 words
The method of claim 33 wherein the phase locking comprises: down converting the PA input signal to a first phase signal by a first down converter; comparing the first phase signal with the edge signal to produce a first phase error signal by a first phase detector; integrating the first phase error signal to generate a control signal by an integrator; and generating the PA input signal based on the control signal by a voltage-controlled oscillator (VCO).
Claim 39
Dependent Claim
68 words
The method of claim 32 wherein updating in the phase feedback path comprises: down converting the output signal to a second phase signal by a second down converter; comparing the second phase signal with the first phase signal to generate a second phase error signal by a second phase detector; and modifying the control parameters based on the second phase error signal by the phase control parameter generator.
Claim 40
Dependent Claim
17 words
The method of claim 32 wherein the control parameters are stored in a phase look-up table (LUT).
Claim 41
Dependent Claim
78 words
The method of claim 31 wherein performing an amplitude compensation comprises: (b1) adjusting a power level of the PA based on an amplitude control parameter in the amplitude feed-forward path by an amplitude DAC; (b2) detecting an output amplitude of the output signal in the amplitude feedback path by an amplitude modulation (AM) detector; and (b3) comparing the detected output amplitude with a predetermined amplitude to generate the amplitude control parameter by an amplitude control parameter generator (ACPG).
Claim 42
Dependent Claim
77 words
The method of claim 37 wherein comparing the detected output amplitude with a predetermined output comprises: storing predetermined amplitude values by an amplitude parameter table; converting the detected output amplitude to an amplitude signal level compatible with the predetermined amplitude values by an amplitude converter; comparing the predetermined amplitude values and the converted amplitude signal by an amplitude comparator, the amplitude comparator generating a control level; and generating a power control signal by an automatic level controller.
Claim 43
Dependent Claim
15 words
The method of claim 37 wherein detecting an output amplitude includes detecting an envelope detector.
Claim 44
Dependent Claim
15 words
The method of claim 37 wherein the predetermined amplitude is stored in an amplitude LUT.
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