Patent ID: 8073044
Filing Date: 2011-12-06
Classification: H03F,H04B,H04L

Abstract:
1. A radio frequency (RF) polar transmitter, comprising: a digital equalizer coupled to receive a digital control signal and a digital amplitude-modulated signal of a variable-envelope modulated signal and operable to use the digital control signal to produce a corrected digital amplitude-modulated signal; a Digital-to-Analog Converter (DAC) operably coupled to receive the corrected digital amplitude-modulated signal and operable to convert the corrected digital amplitude-modulated signal to an analog amplitude modulated-signal; a low pass filter including a filter resistor and coupled to receive the analog amplitude-modulated signal and operable to filter the analog amplitude-modulated signal to produce a filtered analog modulated signal; a calibration circuit operable to measure a variation in the filter resistor of the low pass filter and to produce a digital value representative of the variation in the filter resistor of the low pass filter; and a digital processor coupled to receive the digital value and operable to determine the digital control signal from the digital value, the digital control signal operating to adjust a response of the digital equalizer to compensate for the variation in the filter resistor of the low pass filter.