Volterra series

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

Nonlinear Compensation of Multi-CAP VLC System Employing Clustering Algorithm Based Perception Decision

Abstract: Nonlinearities induced by the electrical amplifiers and the optoelectronic devices can be detrimental effects in visible light communication (VLC) systems. In this paper, clustering algorithm based perception decision (CAPD) is proposed to mitigate the nonlinear distortion in a VLC system. Aided by CAPD nonlinear compensation, we experimentally demonstrate a multiband CAP modulated VLC system consisting of a red light-emitting diode as a transmitter and a p-i-n photodiode based differential receiver. The system performances including the Q factor, bit error rate (BER), and computational complexity are thoroughly investigated when using a pure linear blind equalization scheme (modified cascaded multimodulus algorithm, M-CMMA) and when using hybrid linear and nonlinear equalizers (M-CMMA + Volterra series based nonlinear equalizer). The experiment results show that compared to pure linear equalizer case, the measured BER can be enhanced up to 1e−6, correspondingly the Q factor of each subband can be improved for around 1.6–2.5 dB by employing CAPD. The CAPD method can outperform the Volterra series based nonlinear equalizer with a lower BER value (at least 10% reduction) and relatively lower complexity. To the best of our knowledge, this is the first time that the clustering algorithm in machine learning is successfully applied to VLC systems.

Mitigation of intra-channel nonlinearities using a frequency-domain volterra series equalizer

Abstract: We apply a frequency-domain Volterra series nonlinear equalizer to a 20 Gbaud NRZ-QPSK signal propagated over 1600 km. Using 2 samples/symbol we obtain a 2 dB improvement on the nonlinear tolerance over backward propagation split-step Fourier method.

Volterra Behavioral Model for Wideband RF Amplifiers

Abstract: This paper proposes a behavioral modeling approach for the description of nonlinearities in wideband wireless communication circuits with memory. The model is formally derived exploiting the dependence on frequency of the amplifier nonlinear transfer functions and reduce the number of parameters in a general Volterra-based behavioral model. To validate the proposed approach, a commercial amplifier at 915 MHz, exhibiting nonlinear memory effects, has been widely characterized using different stimuli, including two tones, quadrature phase-shift keying wideband code division multiple access, and 16-quadrature amplitude modulation signals with rectangular and root-raised cosine conforming pulses. The theoretical results have been compared with experimental data demonstrating that the model performance is comparable to the well-established memory polynomial model. Calculated and measured baseband waveforms, signal constellation, spectral regrowth and adjacent channel power ratio are tightly coincident in all cases, emphasizing the relevance of the proposed model

Distortion analysis of periodically switched nonlinear circuits using time-varying Volterra series

Abstract: This paper presents a new frequency-domain method for distortion analysis of general periodically switched nonlinear circuits. It generalizes Zadeh's time-varying network functions and bifrequency transfer functions from linear time-varying systems to nonlinear time-varying systems. The periodicity of time-varying network functions of linear and nonlinear periodically time-varying systems is investigated using time-varying Volterra series. We show that a periodically switched nonlinear circuit can be characterized by a set of coupled periodically switched linear circuits. Distortion of the periodically switched nonlinear circuit is obtained by solving these linear circuits. This result is a generalization of the multi-linear theory known for nonlinear time-invariant circuits. We also show that the aliasing effect encountered in noise analysis of switched analog circuits exists in distortion analysis of periodically switched nonlinear circuits. Computation associated with the folding effect can be minimized by using the adjoint network of periodically switched linear circuits, in particular, the frequency reversal theorem. The method presented in this paper has been implemented in a computer program. Distortion of practical switched circuits is analyzed and the results are compared with SPICE simulation.

Distortion analysis of Miller-compensated three-stage amplifiers

Abstract: This paper proposes a theoretical approach for evaluating distortion in the frequency domain of three-stage amplifiers adopting two commonly used compensation techniques, namely the nested Miller (NM) and the reversed NM. The analysis is based on appropriate amplifier modeling and on the assumption that the nonlinearity generated by each stage is static. Calculations are thus greatly simplified avoiding complex methods based on the Volterra series. Only dominant contributions need to be taken into account, thereby highlighting those mechanisms generating distortion and their features in the frequency domain. Moreover, the adopted approach provides useful design guidelines and explains why the NM compensation technique allows generally better linearity performance at low frequency and why the reversed NM is best suited to high frequencies. Simulation results with Spectre on two transistor-level CMOS circuits are also provided and found to be in very good agreement with expected results.