Multisinusoidal Input Research Articles

Nonlinear performance of the mixed translinear loop

The nonlinear behaviour of the mixed translinear loop is analysed. Closed-form expressions are obtained for the harmonic and intermodulation components resulting from a multisinusoidal input signal. These expressions can be used to predict the limiting values of the input current for a prespecified tolerable distortion percentage.

Harmonic and intermodulation performance of some abrupt and weak nonlinearities

A computationally simple algorithm for mathematical modelling of weakly and abrupt nonlinearities, using Fourier-series representation, is presented. Using this mathematical model one can obtain closed-form expressions, in terms of the ordinary Bessel functions, for the amplitudes of the harmonic and intermodulation products at the output of an abrupt or weak nonlinearity excited by a multisinusoidal input.

Linearization techniques for bipolar emitter-coupled pairs: a comparative study

Bipolar emitter-coupled pairs are basic building blocks in many analogue integrated circuits. Because of the high intermodulation and adjacent channel radiation performance requirements, state of the art communication electronic circuits require extremely linear transfer functions of the emitter-coupled pairs and several techniques have been proposed for their linearization. In this paper, a comparative study of these linearization techniques is presented. A simple procedure for approximating the transfer characteristics of an emitter-coupled pair is proposed and closed-form expressions are obtained for the amplitudes of the intermodulation products at the output of an emitter-coupled pair excited by a multisinusoidal input signal. Using these expressions comparison between the different linearization techniques can be performed and the optimum linearization technique required to meet a predetermined intermodulation performance can be decided.

An improved analysis for the bipolar linear transconductor

An improved analysis for the bipolar linear transconductor, assuming a finite value for the transistor current-gain β, is presented. A new expression for the normalized input-voltage as a function of the normalized output-current is obtained. A Fourier-series model is presented for this current-voltage relationship. Closed-form expressions are also derived for the harmonic and intermodulation components resulting from exciting the bipolar linear transconductor by a multisinusoidal input voltage. These expressions can be used to predict the limiting values of the input voltage amplitudes for a prescribed tolerable distortion percentage.

An approximate analysis and its application to the nonlinear performance of three MOSFET transconductance amplifiers

A simple procedure for approximating the input-output characteristic of nonlinear electronic circuits is presented. Using this procedure, closed-form analytical expressions, in terms of the ordinary Bessel functions, are obtained for the output spectra of a nonlinear electronic circuit resulting from a multisinusoidal input. Using these expressions, the nonlinear performance of three basic MOSFET transconductance amplifiers is considered in an attempt to determine the transistor parameters for best linearity.

Parameter Identification for Unsteady Aerodynamic Systems by the Modulating Function Technique

The longitudinal dynamics of aircraft is extended into the unsteady aerodynamic regime by the inclusion of indiciai functions. A ‘grey box’ identification problem is formulated with a least squares algorithm for the modulating function technique and Schroeder-phased multisinusoidal input signals are used to improve the noise properties of the algorithm.

Multivariable Plant Set Estimation using Multisinusoidal Input Designs

A frequency domain method is developed for statistical multivariable plant set estimation. The estimation of a plant “set” rather than a point estimate is required to support many methods of modern robust control design. Results for the multivariable case extend earlier results developed for the single-input single-output (SISO) case. The approach here is based on using multisinusoidal input designs, and acquiring multivariable data from a sequence of single-input multiple-output (SIMO) experiments. Estimators of the plant, output noise, and uncertainty are defined by using the Discrete Fourier Transform (DFT), and statistical properties of the estimators are presented. These properties lead to a precise characterization of the plant set to a specified statistical confidence, e.g., (1-α)-100%.

An Approximate Analysis and Its Application to The Non-Linear Performance of Three Mosfet Transconductance Amplifiers

A simple procedure for approximating the input-output characteristic of non-linear electronic circuits is presented. Using this procedure, closed-form analytical expressions, in terms of the ordinary Bessel functions, are obtained for the output spectra of a non-linear electronic circuit resulting from a multisinusoidal input. Using these expressions, the non-linear performance of three basic MOSFET transconductance amplifiers is considered in an attempt to determine the transistor parameters for best linearity.

Large signal analysis of optical directional coupler modulators

Expressions are obtained for the output harmonic and intermodulation products of optical electrical coupler modulators driven by multisinusoidal input signals. The special case of relatively small input amplitudes is considered. The results are verified by comparisons with previously published results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Prediction of RFI demodulation in BiFET, BiMOS and CMOS operational amplifiers

A model is proposed for the differential input-voltage/output-current characteristic of JFET and MOSFET differential amplifiers. Using this model a closed-form expression is derived for the output signal of BiFET, BiMOS and CMOS operational amplifiers excited by a multisinusoidal input signal. Using this expression, the RFI demodulation in these operational amplifiers can be predicted.

The isolation of undistorted sinusoids in real time

A single-input, multiple-output adaptive filter that takes a multisinusoidal input signal and produces the individual sinusoids at each of the outputs is described. The individual outputs have identical amplitudes and phases to the components of the original input signal. The filter can be adapted in real time using approximate Gauss-Newton updates without requiring any matrix operations or divisions. The filter is an extension of a cascade adaptive IIR (infinite impulse response) notch filter reported previously. The filter is very amenable to being realized using custom ICs or DSP (digital signal processing) ICs, as no divisions are required and most of the filter is composed of identical biquads (which are very insensitive to the errors caused by finite accuracy in fixed-point implementations). The structure is especially good at isolating small-amplitude sinusoids when in the proximity of much larger sinusoids of unknown frequencies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Harmonic and intermodulation performance of active integrated-optic waveguides

An empirical formula is developed for the static input/output optical characteristic of the active integrated-optic waveguide. Using this formula, closed-form analytical expressions, in terms of the ordinary Bessel functions, are obtained for the output optical components resulting from a modulated multisinusoidal optical input. Using these expressions the effect of the wavelength of the light input, the guide width, the modulation depth and the optical power for transperancy on the harmonic and intermodulation performance of the active integrated-optic waveguide can be studied.

Nonlinear distortion due to early voltage effect in the current source transistors of bipolar transconductance stages

A simple formula is presented for the input/output characteristics of the bipolar transconductance stage taking into account the Early voltage effect of the current source transistors. Also, a closed-form expression is derived for the output signal of a transconductance stage excited by a multisinusoidal input signal.

Prediction of RFI demodulation in bipolar operational amplifiers

A model is proposed for the inputoutput nonlinearity and the gain-frequency characteristic of a typical bipolar operational amplifier circuit. Using this model a closed-form expression is derived for the output signal of the operational amplifier circuit excited by a multisinusoidal input signal. Using this expression, the RFI demodulation in the operational amplifier circuit is predicted.

Spectral response of nonlinear magnetic conductors

A general procedure for predicting the amplitudes of the magnetic induction components, resulting from multisinusoidal excitation of a non linear magnetic conductor, is presented. The magnetisation curve of the magnetic conductor is represented by a sine series. The amplitudes of the magnetic induction components are expressed in terms of the Bessel functions with arguments pro portional to the amplitudes of the exciting multi-sinusoidal input.

Non-linear model for single-channel MOSFET integrated circuit differential amplifier

A simple formula is presented for the relationship between an input differential voltage and the corresponding output differential current of single-channel MOSFET integrated circuit differential amplifiers. In addition, a closed-form expression is derived for the output signal of a differentia! amplifier excited by a multisinusoidal input signal.

A non-linear model for microwave GaAs FET amplifiers

Abstract A Fourier-series model is presented for microwave GaAa FET amplifiers exhibiting both amplitude non-linearity and amplitude modulation to phase modulation conversion. A closed-form expression is also derived for the intermodulation products at the output, of an amplifier excited by a multisinusoidal input signal. Typical results are compared with previously published measurements and calculations

Non-linear model for FET differential amplifier

A simple formula is presented for the relationship between an input differential voltage and the corresponding output differential current of an FET differential amplifier. Also, a closed-form expression is derived for the output signal of a differential amplifier excited by a multi-sinusoidal input signal.

Improved analysis of the harmonic and intermodulation performance of operational amplifiers

Simple formulas are presented for the nonlinear voltage-controlled current sources of operational amplifiers with strong inversion MOSFET, weak inversion MOSFET, JFET and bipolar input transistors, and are shown to fit the nonlinearities very well. Furthermore, closed-form expressions are derived for the output signal and intermodulation product levels of an operational amplifier excited by a multisinusoidal input signal. The results are presented in a form suitable for predicting the influence of the nonlinear voltage-controlled current source on the performance of electronic circuits incorporating operational amplifiers.

A nonlinear model for the GaAs ballistic diode

A simple formula is presented for the current-voltage relationship of the GaAs ballistic diode. Also, closed-form expressions are derived for the harmonics and intermodulation current contents resulting from exciting the diode by a multisinusoidal input voltage.