A modified model and linearization method for solid state power amplifier

Abstract

In this paper we present a modified model of solid state power amplifiers. Also using the mathematical concept of best approximation in Hilbert spaces, a predistorter structure is suggested to compensate both AM/AM and AM/PM conversion characteristics of a solid state power amplifier. To verify the effects of this linearization we generally consider it in a QAM signal transmission in an additive white Gaussian noise channel and the results are compared with the ideal linear case. It is shown that the presented method is able to compensate the nonlinearity up to a good extent. The performance of proposed method has been analyzed in frequency domain through spectrum simulations. To prove the validity of presented method we have made similar considerations on continuous spectrum.

Quantifying and cancelation memory effects in high power amplifier for OFDM systems

“…So, we proposed this new method [18] in order to avoid the numerical difficulty associated with hf À1 ðxÞ; (20) can be written as…”

“…Now, with knowing f -1 , the intermediate variable v(k) can be obtained from (18). By obtaining v(k), the unknown Linear Time Invariant (LTI) parameter, b n , (15) can be acquired based on normalized least mean square (NLMS) when the quadrative criterion min{ P k=1 K (e(k)) 2 } is minimized [19] as follows:…”

“…where eðkÞ ¼ vðkÞ À d vðkÞ in which v(k) is achieved from (15) and d vðkÞ has been defined in (18). Meanwhile, l is a normalized step-size constant with 0 \ l \ 2 which controls stability and the convergence speed of the algorithm.…”

New single-parameter models for nonlinear electronic systems and its use in predicting intermodulation performance

“…Similar to the model presented in [21], this model does not provide a single mathematical expression stretching over the full range of input. In [5] another four-parameter model has been presented. This model is formed of one portion and caters for nonlinear characteristics starting with a linear part, for relatively low inputs, and followed by a nonlinear part at relatively large inputs.…”

“…This model is formed of one portion and caters for nonlinear characteristics starting with a linear part, for relatively low inputs, and followed by a nonlinear part at relatively large inputs. Unfortunately, the models proposed in [5,8,11,21,23,28] can not yield closed-form expressions for the amplitudes of the output intermodulation products resulting from a multisinusoidal input. Thus, recourse to numerical solutions using computer aided tools is necessary.…”