Amplitude modulator

A circuit for amplitude modulating a carrier signal, comprising:

• circuitry for splitting a carrier signal into first and second paths;
• circuitry for phase modulating the carrier signal on the first path;
• circuitry for receiving a baseband signal that is not derived from the carrier signal, wherein the baseband signal affects 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 signal.

A method for amplitude modulating a carrier signal, comprising:

• splitting a carrier signal into first and second paths;
• constant-envelope phase modulating the carrier signal on the first path;
• constant-envelope phase modulating the carrier signal on the second path;
• amplifying the phase modulated carrier signal on the first path;
• amplifying the phase modulated carrier signal on the second path;
• 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
• wherein a first feedback loop couples the amplitude modulated output signal to 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.

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;
• phase modulating the carrier signal on the second path;
• 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;
• wherein a first feedback loop couples the amplitude modulated output signal to 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 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;
• phase modulating the carrier signal on the second path;
• 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;
• wherein a first feedback loop couples the amplitude modulated output signal to 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;
• wherein a second feedback loop is coupled to an output of the amplitude modulated output signal;
• and
• using a baseband signal and a signal from the second feedback loop to make an envelope amplitude of the amplitude modulated output signal linearly proportional to an amplitude of the baseband

A circuit for modulating a carrier signal, comprising:

• circuitry for creating from a carrier signal two sub-signals;
• 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 inputs the carrier signal and the modulated carrier signal.

A method for modulating a carrier signal, comprising:

• creating two electronic sub-signals from a carrier signal;
• 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 an input the modulated carrier signal.