Patent ID: 7433657
Filing Date: 2008-10-07
Classification: H04L

Abstract:
1. A transmitter comprising: a signal generator having an input, the signal generator operable to produce a first signal at a first frequency and the first signal having an associated first frequency characteristic, the first signal containing frequency-related information, the first signal produced in accordance with a signal received at the input of the signal generator; an amplification stage, coupled to the signal generator, having an output and operable to receive the output of the signal generator, the output of the amplification stage being dependent on both the first signal and an incoming amplitude modulating signal; a detection circuit, coupled to the output of the signal generator, having an output and operable to detect the first frequency-related characteristic of the output of the signal generator and generate a signal representative of the first frequency-related characteristic; a comparison circuit, coupled to the detection circuit, having an output and operable to compare the signal representative of the first frequency-related characteristic and a signal representative of a second frequency-related characteristic, the output of the comparison circuit indicative of a difference between the first frequency-related characteristic and the second frequency-related characteristic; a loop filter, coupled to the comparison circuit and to the signal generator, operable to output a signal to the signal generator in response to the output of the comparison circuit, the loop filter operable to be clocked by an input clock at a second frequency; a clock circuit, coupled to the comparison circuit and to the loop filter, for providing the input clock to the loop filter, the clock circuit operable to compare the first frequency and the second frequency; and wherein the clock circuit is operable to change the second frequency based upon a relationship between the first frequency and the second frequency.