Pseudo-polar modulation for radio transmitters
First Claim
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1. A method of modulating a radio transmitter, the method comprising:
- generating an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of an information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal; and
forming a complex signal having substantially the same phase angle variation as the I and Q components of the information signal so that the product of the complex signal and the amplitude modulation signal is substantially equal to the information signal.
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Abstract
Methods of modulating a radio transmitter. An amplitude modulation signal is generated based on in-phase (I) and quadrature (Q) components of an information signal, and so that it has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal. A complex signal is formed that has substantially the same phase angle variation as the I and Q components of the information signal so that the product of the complex signal and the amplitude modulation signal is substantially equal to the information signal.
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Citations
38 Claims
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1. A method of modulating a radio transmitter, the method comprising:
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generating an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of an information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal; and
forming a complex signal having substantially the same phase angle variation as the I and Q components of the information signal so that the product of the complex signal and the amplitude modulation signal is substantially equal to the information signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of controlling a power amplifier in a radio transmitter, the method comprising:
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generating a power amplifier saturation control signal based on in-phase (I) and quadrature (Q) components of an information signal;
generating a drive signal based on the information signal; and
controlling the power amplifier with the power amplifier saturation control signal so that it has a substantially constant amount of saturation while the amplitude of the drive signal changes.
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9. A method of controlling a power amplifier in a radio transmitter, the method comprising:
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generating first and second information signals, each having in-phase (I) and quadrature (Q) components, from an input signal;
generating an amplitude modulation signal based on magnitude of the I and Q components of the second information signal;
generating a drive signal to the power amplifier based on the I and Q components of the first information signal; and
varying amplification of the drive signal by the power amplifier based on the amplitude modulation signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A radio transmitter comprising:
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a pseudopolar modulation generator that is configured to generate an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of an information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal;
a quadrature modulator that is configured to combine the information signal with a carrier signal to generate a channel information signal; and
a power amplifier that is configured to amplify the channel information signal with a variable amplification based on the amplitude modulation signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A wireless terminal comprising:
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a user interface that is configured to generate an information signal from information that is input by a user; and
a radio transmitter comprising;
a pueudopolar modulation generator that is configured to generate an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of the information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal;
a quadrature modulator that is configured to combine the information signal with a carrier signal to generate a channel information signal; and
a power amplifier that is configured to amplify the channel information signal with a variable amplification based on the amplitude modulation signal.
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37. A wireless base station comprising:
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a wireless network that is configured to receive an information signal for transmission to a wireless terminal; and
a radio transmitter comprising;
a psuedopolar modulation generator that is configured to generate an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of the information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal;
a quadrature modulator that is configured to combine the information signal with a carrier signal to generate a channel information signal; and
a power amplifier that is configured to amplify the channel information signal with a variable amplification based on the amplitude modulation signal.
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38. A computer program product for modulating an information signal having in-phase (I) and quadrature (Q) components for transmission by a radio transmitter, the computer program product comprising program code embodied in a computer-readable storage medium, the computer program code comprising:
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program code for generating an amplitude modulation signal based on in-phase (I) and quadrature (Q) components of the information signal, wherein the amplitude modulation signal has a reduced predetermined characteristic compared to the magnitude of the I and Q components of the information signal;
program code for forming a complex signal having substantially the same phase angle variation as the I and Q components of the information signal so that the product of the complex signal and the amplitude modulation signal is substantially equal to the information signal.
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Specification