Abstract: There is disclosed an adaptive pre-distortion correction circuit for use in an RF transmitter having a transmit path capable of receiving a digital input baseband signal and generating a modulated RF output signal. The adaptive pre-distortion circuit comprises 1) input sampling means coupled to an input of the transmit path for capturing from a first digital input sample of amplitude X; 2) demodulation circuitry coupled to an output of the transmit path for receiving and demodulating the modulated RF output signal to produce a digital output baseband signal; 3) output sampling means coupled to the demodulation circuitry for capturing a first digital output sample corresponding to the first input sample; and 4) processing means for comparing the first digital input sample and the first digital output sample and calculating a pre-distortion correction value corresponding to the amplitude X.

Abstract: An apparatus for performing digital-to-analog conversion with an increased SFDR is provided. An incoming M-bit sample is split into first and second N-bit samples. Preferably, M=16, and N=12. The first N-bit sample contains information relating to the M-bit sample when outside a first predetermined range, and the second N-bit sample contains information relating to the M-bit sample when inside said first predetermined range. A first DAC processes the first N-bit sample to produce a first analog signal, and a second DAC for processing the second N-bit sample to produce a second analog signal. An attenuator attenuates the second analog signal to produce a third analog signal. Finally, a summer is provided adding the first analog signal to the third analog signal representative of the M-bit sample. Preferably, the second predetermined range is a range having a size equal to the range of the second N-bit DAC which is centered at the midpoint of the range the M-bit sample.