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US 7,773,695 B2Granted
Amplitude modulator
AssigneeDominic Kotab
InventorsLiming Zhou, Vadim Kikin
Life of this patent
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Abstract
A circuit for amplitude modulating a carrier signal includes a carrier signal input, circuitry for splitting the carrier signal into first and second paths, circuitry for phase modulating the carrier signal on the first path, circuitry for phase modulating the carrier signal on the second path, and circuitry for combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal. Feedback loops virtually eliminate residual phase shift and make the amplitude modulated output signal linearly proportional to the baseband signal.
Claims25
A circuit for amplitude modulating a carrier signal, comprising:
- a carrier signal input;
- circuitry for splitting the carrier signal into first and second paths;
- circuitry for phase modulating the carrier signal on the first path;
- circuitry for phase modulating the carrier signal on the second path;
- circuitry for combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal;
- and
- a first feedback loop coupling the amplitude modulated output signal to the circuitry for phase modulating the carrier signal on the second path but not to the circuitry for phase modulating the carrier signal on the first path, the first feedback loop being for reducing a residual phase variation of the amplitude modulated output signal.
4 more elements
A method for amplitude modulating a carrier signal, comprising:
- splitting a carrier signal into first and second paths;
- phase modulating the carrier signal on the first path;
- receiving a baseband signal that is not derived from the carrier signal, wherein the baseband signal affects the circuitry for phase modulating the carrier signal on the first path;
- phase modulating the carrier signal on the second path;
- and
- combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated signal.
3 more elements
A circuit for amplitude modulating a carrier signal, comprising:
- a carrier signal input, wherein the carrier signal is an electronic signal;
- circuitry for splitting the carrier signal into first and second paths;
- circuitry for constant-envelope phase modulating the carrier signal on the first path;
- circuitry for constant-envelope phase modulating the carrier signal on the second path;
- a nonlinear amplifier on the first path for amplifying the phase modulated carrier signal on the first path;
- a nonlinear amplifier on the second path for amplifying the phase modulated carrier signal on the second path;
- circuitry for combining the amplified phase modulated carrier signal on the first path with the amplified phase modulated carrier signal on the second path for generating an amplitude modulated output signal;
- and
- a first feedback loop coupling the amplitude modulated output signal to the circuitry for phase modulating the carrier signal on the second path, the first feedback loop controlling a phase shifter in the circuitry for phase modulating the carrier signal on the second path.
6 more elements
A circuit for amplitude modulating a carrier signal, comprising:
- a carrier signal input, the carrier signal being an electronic signal;
- circuitry for splitting the carrier signal into first and second paths;
- circuitry for phase modulating the carrier signal on the first path;
- circuitry for phase modulating the carrier signal on the second path;
- circuitry for combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal;
- a first feedback loop coupling the amplitude modulated output signal to the circuitry for phase modulating the carrier signal on the second path, the first feedback loop being for reducing a residual phase variation of the amplitude modulated output signal.
3 more elements
A circuit for amplitude modulating a carrier signal, comprising:
- a carrier signal input;
- circuitry for splitting the carrier signal into first and second paths;
- circuitry for phase modulating the carrier signal on the first path;
- circuitry for phase modulating the carrier signal on the second path;
- circuitry for combining the phase modulated carrier signal on the first path with the phase modulated carrier signal on the second path for generating an amplitude modulated output signal;
- a baseband signal input;
- a first feedback loop coupling the amplitude modulated output signal to the circuitry for phase modulating the carrier signal on the second path, the first feedback loop being for reducing a residual phase variation of the amplitude modulated output signal;
- a second feedback loop coupled to an output of the amplitude modulated output signal;
- and
- linearizing circuitry coupled to the baseband signal input and second feedback loop for making an envelope amplitude of the amplitude modulated output signal linearly proportional to an amplitude of the baseband signal.
7 more elements
A method for modulating a carrier signal, comprising:
- creating from a carrier signal two sub-signals using circuitry;
- phase modulating at least one of the sub-signals relative to the other;
- and
- combining the sub-signals to produce a modulated carrier signal,
- wherein at least one of the sub-signals is phase modulated under control of a feedback loop having as inputs the carrier signal and the modulated carrier signal.
2 more elements
A system for modulating a carrier signal, comprising:
- circuitry for creating two electronic sub-signals from a carrier signal;
- circuitry for phase modulating at least one of the sub-signals relative to the other;
- and
- circuitry for combining the sub-signals to produce a modulated carrier signal,
- wherein at least one of the sub-signals is phase modulated under control of a feedback loop having as an input the modulated carrier signal.
2 more elements
Dependencies are inferred from the claim text.