COMPENSATION OF NONLINEAR DISTORTION IN INERTIAL DEVICES

In any communication system the main problem block is a power amplifier since when it operates in high efficiency mode makes nonlinear distortion in the amplified signal. This paper presents a method for compensation distortions in nonlinear inertial devices (NID). We also estimate the distortion of digital communication system signals with the introduction of compensation algorithms for a nonlinear amplifier by simulation. The compensation is carried out with a digital predistortion device (DPD), which is involved in front of NID and actually implements the reverse transformation of NID. We provide a research for the models of NID in the form of a typical radio engineering parts: a finite impulse response (FIR) filter - a non-linear Saleh model - FIR filter, the input of which provides with an OFDM signal. We obtain the resulting dependence characteristic between the instantaneous values of envelopes of output and at the input at discrete points in time (AM-AM), based on values of the phase difference output and input signals from the instantaneous values of the envelope signal at the input device at discrete points in time (AM-PM) signals and spectra with DPD NID by simulation on a computer. Finally, we assumed that the simulation shows that the inclusion of the control before the NID can significantly increase the dynamic range or energy efficiency of the NID while maintaining the level of interference of nonlinear distortions. Also, we describe the results of comparison with the DPD constructed on the basis of a polynomial model with memory are also presented.