Volterra series

About: Volterra series is a research topic. Over the lifetime, 2731 publications have been published within this topic receiving 46199 citations.

Analytical investigation and evaluation of pulse broadening factor propagating through nonlinear optical fibers (traditional and optimum dispersion compensated fibers)

Abstract: In this paper, analytical relation for pulse width evolution and broadening in fiber systems using the Volterra series transfer function (VSTF) in linear and nonlinear cases are derived. This evaluation is done for traditional and optimum dispersion compensated fibers. Effects of group velocity dispersion (GVD) and self-phase modulation (SPM) are taken into account. It is shown that the analytical formulation can be applied to design and analysis the long hauls practical systems, and is helpful in understanding the pulse distortion caused by the interaction between SPM and GVD. The proposed relations are extracted analytically and for the first time pulse broadening factor in general case is derived.

On reduced-complexity approximations of quadratic filters

Abstract: Among the various mathematical representations of nonlinear systems, a popular description is given by means of the discrete-time Volterra series. In this paper we first briefly review the relevant nonlinear system identification techniques, with reference in particular to nonlinear systems with lengthy memory. In such cases, a parallel-cascade structure has been proved to be very effective since it is able to provide an arbitrarily close approximation, in the mean square error (MSE) sense, for a broad class of systems to be modelled. The parallel-cascade structure is indeed an exact representation for a quadratic filter, obtained by means of a matrix decomposition technique: we recall such a technique and then we show how it is possible to apply it for the adaptive identification of quadratic systems with large time delays. >

Dynamical realizations of finite Volterra series

Abstract: In this paper we investigate the structure of minimal realizations of finite volterra series, within the class of nonlinear, analytic systems. The structure of Nilmanifolds described by A. Malcev is used to show that the natural state space of these realizations is a vector space. Additionally it is shown that minimal realizations of finite Volterra series can be viewed as cascades of linear subsystems with polynomic link maps. The dimensions of these subsystems do not depend on the minimal realization, and an algorithm is given to compute them from the kernels.

Augmented Volterra predistortion for the joint mitigation of power amplifier and I/Q modulator impairments in wideband flexible radio

Abstract: Dynamic and flexible RF spectrum access through software-defined radio technologies is known to be limited by transmitter RF impairments, most notably spurious emissions due to mixer I/Q imbalance and power amplifier nonlinearity. In this article, a novel digital predistortion structure is developed for joint mitigation of frequency-dependent I/Q imbalance and dynamic nonlinear effects of amplifiers in wideband direct-conversion radio transmitters. The developed structure consists of two Volterra series in parallel, with built-in sparsity in the kernels, and is shown to be linear in parameters thus requiring only one feedback path for joint parameter identification. Extensive simulation results demonstrate significant improvements in transmitter linearization performance, compared to state-of-the-art memory polynomial based linearizers. Thus, the developed predistortion solution can be seen as one key enabling technique towards practical deployment of SDR technology with digitally-enhanced wideband RF front-ends.