Pseudo-polar modulation for radio transmitters
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorPaul W. Dent
Life of this patent
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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.
Claims38
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.
A method of controlling a power amplifier in a radio transmitter, the method comprising:
- 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.
A method of controlling a power amplifier in a radio transmitter, the method comprising:
- 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.
A radio transmitter comprising:
- 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.
A wireless terminal comprising:
- 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.
A wireless base station comprising:
- 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.
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:
- 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.
Dependencies are inferred from the claim text.