20 documents found, page 1 of 2
Dynamic supply voltage control for PA output power correction under variable lo...
Gonçalves, Cristiano F.; Barradas, Filipe M.; Nunes, Luís C.; Cabral, Pedro M.; Pedro, José CarlosThis article presents an automatic system that is able to dynamically restore the output power capability of a power amplifier (PA) under variable loading scenarios. This is accomplished by dynamically adapting the supply voltage, VDD, of the PA according to the developed theoretical model. To dynamically vary VDD, a GaN dc–dc converter, based on the commercial EPC 9067 Demo Board, was used. The load is measure...
A compact impedance measurement solution for systems operating in load varying ...
Gonçalves, Cristiano F.; Barradas, Filipe M.; Nunes, Luís C.; Cabral, Pedro M.; Pedro, José CarlosThis paper presents a compact solution for impedance calculation obtained from low phase resolution stationary wave measurements, for RF power systems operating in load varying scenarios. The implemented system is based on a bi-directional coupler and makes use of the stationary wave periodicity, which is synthesized and measured via a digital phase shifter, a power combiner, and an envelope detector, in a spec...
On the Usage of Harmonic Balance to Simulate Memristive Devices and Circuits
Kailasam, Rathnakannan; Alves, Luis Nero; Mendes, Joana Catarina; Pedro, José CarlosThis paper proposes the usage harmonic balance method to find the steady state solution on memristive devices and circuits. Harmonic balance is a well-established simulation tool often used to find the periodic steady state solution of circuits involving non-linear elements. It is a particularly efficient method when the focus is on the characterization of the frequency-domain behavior of some quantity in the c...
Memristor State-Space Embedding
Dghais, Wael; Alves, Luis Nero; Mendes, Joana Catarina; Rodriguez, Jonathan; Pedro, José CarlosThis paper presents a procedure for the determination of the dimensionality of the state space of a memristive device. The state space dimensionality of a device corresponds to the minimum number of time delayed values/derivatives of the voltage and current required to represent the device dynamics for a specified set of inputs. The algorithm is based on the observed time domain voltage-current (i.e. input-outp...
A multiple-line double multirate shooting technique for the simulation of heter...
Oliveira, Jorge dos Santos Freitas de; Pedro, José CarlosThis paper describes a computer-aided design tool especially conceived for the efficient time-domain simulation of strongly nonlinear mixed digital, baseband, and RF circuits operating in multiple time scales. The proposed numerical method is based on a 3-D envelope oriented technique over an innovative multiple-line double multirate shooting strategy, and is tested with an illustrative circuit example. Signifi...
An innovative time-domain simulation technique for strongly nonlinear heterogen...
Oliveira, Jorge dos Santos Freitas de; Pedro, José CarlosWith the advent of wireless transceiver reconfigurability, a need has been felt to take profit of digital signal processing tools, this way increasing RF circuits’ complexity and heterogeneity. Having this objective in mind, this paper presents an analytical formulation and a novel numerical method for simulating, in a very efficient way, strongly nonlinear heterogeneous RF circuits running in three different t...
A new time-domain simulation method for highly heterogeneous RF circuits
Oliveira, Jorge dos Santos Freitas de; Pedro, José CarlosThis paper describes a new time-domain simulation method particularly amenable for highly heterogeneous nonlinear RF circuits as modern wireless transceivers that combine analog RF and both analog and digital base-band circuitry. It uses innovative multi-rate Runge-Kutta algorithms applied to the envelope transient method over a time-domain periodic steady-state technique (shooting), to efficiently resolve stro...
An efficient time-domain simulation method for multirate RF nonlinear circuits
Oliveira, Jorge dos Santos Freitas de; Pedro, José CarlosThis paper describes a new computer-aided design tool especially conceived for the efficient time-domain simulation of highly heterogeneous nonlinear wireless communication circuits, i.e., combining RF and baseband analog circuitry and digital components. Using multirate Runge–Kutta algorithms within a multitime framework, to benefit from the different rates of variation of slowly varying (latent) and fast-vary...
Practical issues on RF modelling of multi-rate nonlinear Systems
Cunha, Telmo Reis; Pedro, José CarlosThis paper presents an analysis on practical issues regarding the use of RF modelling of multi-rate nonlinear systems. Multi-rate systems are characterizcd by a frequency spectrum concentrated on distinct and separated frequency bands. This characteristic makes impossible the use of baseband models (that consider frequency shifting of the system spectrum), and so, RF modelling is naturally applied. Noticing the...
State-of-art nonlinear electronic design automation tools for Microwave/RF circ...
Pedro, José CarlosThis paper presents an overview of state-of-theart techniques for the analysis and simulation of microwave and RF nonlinear circuits. It is the result of the work done for preparation of “Provas de Agregação” (the habilitation degree for full professorship in Portuguese Universities) of its author, and the various seminars given on this subject. Using a pedagogical approach, the paper first states the problem o...