Patent ID: 7072421
Filing Date: 2006-07-04
Classification: H03C,H03F,H04L

Abstract:
1. 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; and 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 input, a controlled oscillator output that produces the phase signal 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, and wherein the quadrature modulator is included within 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.