IQ modulation systems and methods that use separate phase and amplitude signal paths and perform modulation within a phase locked loop

A modulation system comprising:

• a quadrature modulator that modulates in-phase and quadrature-phase signals to produce a modulated signal;
• a phase tracking subsystem that is responsive to the quadrature modulator to produce a phase signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal;
• an amplitude tracking subsystem that is responsive to the quadrature modulator to produce an amplitude signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal, wherein the amplitude tracking subsystem comprises an automatic gain control subsystem that is responsive to the modulated signal to produce the amplitude signal;
• an amplifier having a signal input, an amplitude control input and an output, wherein the signal input is responsive to the phase signal and the amplitude control input is responsive to the amplitude signal;
• wherein the phase tracking subsystem comprises a phase locked loop that includes a controlled oscillator having a controlled oscillator output that produces the phase signal and wherein the quadrature modulator is included within the phase locked loop;
• and
• wherein the automatic gain control subsystem further comprises:
• a first envelope detector that is responsive to the modulated signal;
• a second envelope detector that is responsive to the phase locked loop;
• and
• a comparator that is responsive to the first and second envelope detectors to produce the amplitude signal.

A modulation system comprising:

• a quadrature modulator that modulates in-phase and quadrature-phase signals to produce a modulated signal;
• a phase tracking subsystem that is responsive to the quadrature modulator to produce a phase signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal;
• an amplitude tracking subsystem that is responsive to the quadrature modulator to produce an amplitude signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal, wherein the amplitude tracking subsystem comprises an automatic gain control subsystem that is responsive to the modulated signal to produce the amplitude signal;
• an amplifier having a signal input, an amplitude control input and an output, wherein the signal input is responsive to the phase signal and the amplitude control input is responsive to the amplitude signal;
• wherein the phase tracking subsystem comprises a phase locked loop that includes a controlled oscillator having a controlled oscillator output that produces the phase signal and wherein the quadrature modulator is included within the phase locked loop
• wherein the automatic gain control subsystem further comprises:
• a first envelope detector that is responsive to the modulated signal;
• a second envelope detector that is responsive to the amplifier;
• and
• a comparator that is responsive to the first and second envelope detectors to produce the amplitude signal.

A modulation system comprising:

• a quadrature modulator that modulates in-phase and quadrature-phase signals to produce a modulated signal;
• a phase tracking subsystem that is responsive to the quadrature modulator to produce a phase signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal;
• an amplitude tracking subsystem that is responsive to the quadrature modulator to produce an amplitude signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal;
• an amplifier having a signal input, an amplitude control input and an output, wherein the signal input is responsive to the phase signal and the amplitude control input is responsive to the amplitude signal;
• wherein the phase tracking subsystem comprises a phase locked loop that includes a controlled oscillator having a controlled oscillator output that produces the phase signal and wherein the quadrature modulator is included within the phase locked loop;
• and
• wherein the amplitude tracking subsystem further comprises an envelope detector that is responsive to the modulated signal to produce the amplitude signal.

A modulation method comprising:

• modulating in-phase and quadrature signals to produce a modulated signal;
• producing a phase signal from the modulated signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal using a phase locked loop that includes a controlled oscillator having a controlled oscillator input, a controlled oscillator output and a feedback loop between the controlled oscillator input and the controlled oscillator output, the feedback loop including a mixer that is responsive to a local oscillator, wherein the modulating is performed in the feedback loop between the controlled oscillator output and the mixer, between the local oscillator and the mixer, or between the mixer and the controlled oscillator input;
• producing an amplitude signal from the modulated signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal;
• and
• amplifying the phase signal at a gain that is varied in response to the amplitude signal.

A modulation method comprising:

• modulating in-phase and quadrature signals to produce a modulated signal;
• producing a phase signal from the modulated signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal using a phase locked loop that includes a controlled oscillator having a controlled oscillator output, wherein the modulating is performed within the phase locked loop;
• producing an amplitude signal from the modulated signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal;
• amplifying the phase signal at a gain that is varied in response to the amplitude signal;
• wherein the producing an amplitude signal from the modulated signal comprises automatic gain controlling the modulated signal to produce the amplitude signal;
• and
• wherein the automatic gain controlling comprises:
• envelope detecting the modulated signal;
• envelope detecting a signal in the phase locked loop;
• and
• comparing the envelope detected modulated signal and the envelope detected signal in the phase locked loop to produce the amplitude signal.

A modulation method comprising:

• modulating in-phase and quadrature signals to produce a modulated signal;
• producing a phase signal from the modulated signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal using a phase locked loop that includes a controlled oscillator having a controlled oscillator output, wherein the modulating is performed within the phase locked loop;
• producing an amplitude signal from the modulated signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal;
• amplifying the phase signal at a gain that is varied in response to the amplitude signal;
• wherein the producing an amplitude signal from the modulated signal comprises automatic gain controlling the modulated signal to produce the amplitude signal;
• and
• wherein the automatic gain controlling comprises:
• envelope detecting the modulated signal;
• envelope detecting the amplified phase signal;
• and
• comparing the envelope detected modulated signal and the envelope detected amplified phase signal to produce the amplitude signal.

A modulation method comprising:

• modulating in-phase and quadrature signals to produce a modulated signal;
• producing a phase signal from the modulated signal that is responsive to phase changes in the modulated signal and that is independent of amplitude changes in the modulated signal using a phase locked loop that includes a controlled oscillator having a controlled oscillator output, wherein the modulating is performed within the phase locked loop;
• producing an amplitude signal from the modulated signal that is responsive to amplitude changes in the modulated signal and that is independent of phase changes in the modulated signal;
• amplifying the phase signal at a gain that is varied in response to the amplitude signal;
• and
• wherein the producing an amplitude signal from the modulated signal comprises:
• envelope detecting the modulated signal to produce the amplitude signal.