On Modelling AM/AM and AM/PM Conversions via Volterra Series

Abstract

Abstract-In this paper, we present the expressions, not published up to now, that describe the AM/AM and AM/PM conversions of communication power amplifiers (PAs) via the Volterra series based nonlinear transfer functions. Furthermore, we present a necessary and sufficient condition of occurrence of the nonzero values of AM/PM conversion in PAs. Moreover, it has been shown that Saleh's approach and related ones, which foresee nonzero level of AM/PM conversion, are not models without memory. It has been also shown that using a polynomial description of a PA does not lead to a nonzero AM/PM conversion. Moreover, a necessary condition of occurrence of an AM/AM conversion in this kind of modelling is existence of at least one nonzero polynomial coefficient associated with its odd terms of degree greater than one.

International Journal of Electronics and Telecommunications

“…1. A fragment of a measured continuous-time signal between two successive instants t0 and Ts, which mean the beginning of the so-called "processing time" defined in [1] and the end of this period, respectively. In this period, it is assumed that the operation of signal averaging takes place in the time from an instant t0 = 0 to an instant Ta.…”

“…As shown in Fig. 1, we assume in our model here that the "processing time" as defined in [1] can be viewed as consisting of two parts: a one related strictly with a signal averaging operation, and the second, from the instant Ta to the instant Ts, devoted strictly to delivering the averaged value to a user (or archiving this value). In the latter time, the signal in Fig.…”

“…T has been shown in [1] that any measuring process can be viewed as a process of sampling signals. In [1], however, only preliminary results have been presented.…”

“…T has been shown in [1] that any measuring process can be viewed as a process of sampling signals. In [1], however, only preliminary results have been presented. That is this basic idea was illustrated via an idealized signal sampling, where the latter refers to as a pointwise operation of sampling.…”

“…The remainder of this paper is organized as follows. In the next section, we present two possibilities of modeling a nonideal sampling, in case of modeling a measuring process, to take into account also nonidealities in a model suggested in [1]: through introducing in it a smearing operation or an averaging operation of samples. We show that in principle these two operations, under some conditions, lead to receiving the same results.…”