IDTF1358NBGI

DPD Demodulator for PA Linearization GENERAL DESCRIPTION This document describes the specification for the IDTF1358 Digital Pre-Distortion Demodulator for PA linearization. This series of devices is offered in 3 variants to cover common UTRA bands. COMPETITIVE ADVANTAGE In typical basestation transmitters, digital pre-distortion is employed to improve the Transmitter performance. The signal coming out of the PA is sampled and the incoming Tx chain I&Q data is pre-distorted to counteract the distortion inherent in the PA. The PA signal is adjusted via a digital step attenuator to a lower level and then sub-sampled at an IF frequency of ~200 MHz which necessitates the need for a highly linear demodulator to downmix to quadrature IF from the Transmit frequency. By sampling IF_I and IF_Q independently and then digitally combining these signals, an effective doubling of the sample rate can be achieved. Any distortion in this path will degrade the performance of the DPD algorithm. By utilizi...