Patent ID: 7725087

Claim:
A direct up conversion transmitter chain, comprising: means for generating an in-phase (I) baseband signal and a quadrature-phase (Q) baseband signal; means for combining the I and Q baseband signals with a radio frequency (RF) carrier signal to generate an RF output signal; means for transmitting the RF output signal; pre-distortion means for down-converting the RF output signal to generate an intermediate frequency (IF) signal, measuring at least one signal impairment in the IF signal to generate at least one signal impairment parameter, and pre-distorting the I and Q baseband signals as a function of the at least one signal impairment parameter to compensate for the measured signal impairment; means for generating a temperature sensor voltage as a function of both ambient temperature in the vicinity of the pre-distortion means and a battery supply voltage; means for generating a reference voltage as a function of both the ambient temperature in the vicinity of the pre-distortion means and the battery supply voltage; and means for estimating an actual ambient temperature value as a function of both the temperature sensor voltage and the reference voltage; wherein the pre-distortion means adjusts the at least one signal impairment parameter by a function of the estimated actual ambient temperature value.