Measurement imperfections impact on the performance of digitally predistorted power amplifiers

This paper presents an study of the impact of analog to digital converter (ADC) impairments on digital pre-distortion (DPD) techniques when applied to RF power amplifiers (PA). The DPD technique is described by a memory polynomial model while the ADC impairments are modeled by quantization noise, random jitter, and the integral nonlinearity (INL); thus, summarizing systematic and random nature of ADC imperfect measurements. It is observed that increased jitter will have a negative impact on the modeling but not so much on the output performance from the pre-distorted PA. Moreover, the ENOB can be used as metric for both the quantization noise and integral nonlinearity and there is a value of ENOB which, if exceeded, do not improve the DPD performance; in this paper it is about 8 bits.