Nonlinear Distortion Analysis Research Articles

Nonlinear distortion analysis on CDMA communicationsystems

The authors give an expression of the estimation of the out-of-band emission levels for a CDMA power spectrum in terms of the third-order intercept point (IP3) and the fifth-order intercept point (IP5), as well as the power level and bandwidth of the signal. This result will be useful in the design of RF power amplifiers for a CDMA wireless system.

Nonlinear distortion analysis in optically prefiltered SCM systems

AbstractWe consider nonlinear distortion due to the optical source and the cross talk produced in optically prefiltered SCM systems. Optimum values for the optical modulation index are calculated and power penalties due to intermodulation distortion are obtained depending on the number of channels and the laser linewidth. © 1995 John Wiley & Sons, Inc.

Nonlinear distortion analysis using maximum-lengthsequences

Information about the nonlinearities of a device under test is obtained using maximum-length sequences. >

Computer aided techniques for the television system engineer

An off-the-shelf program, conveniently adapted and with an extensive library of communication models, was used together with a powerful computer graphics program to simulate a whole TV system. The TV system model was basically composed of a video signal generator, an AM modulator, a transmission filter, a communication channel, a TV receiver with RF amplifier, a mixer, an IF amplifier with the corresponding Nyquist response, a video detector, and a video decoder. The system model was adequate for almost any type of linear and nonlinear distortion analysis . For distortion evaluation an adequate testbed was simulated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Magneto-optic system of a large-acceptance channel for radioactive nuclei separation

The results of calculation and design aspects of separating magnetic channel COMBAS of the tandem of cyclotrons U-400 and U-400M (JINR) are given. The requirements for the magnetic field distribution are formulated on the basis of analysis of nonlinear distortions in heavy-ion beam optics. Pole profiles of the magnets have been optimized using two-dimensional models. Numerical 3-D field simulation of the magnets has been carried out to provide the necessary fringe field distribution.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Nonlinear distortion analysis of p-i-n diode attenuators using Volterra series representations

An application of Volterra series to the analysis of a network with nonlinear elements represented by Volterra series is presented. For the equivalent circuit of this network, the outputs of the n th-order nonlinear sources are given in the frequency domain. The model of the p-in diode in a form of the Volterra series, which was proposed earlier by the author, is implemented and the results of the analysis are used to derive the cross-modulation coefficient for a \pi -type attenuator with three p-in diodes. Computation results are compared with those obtained from measurements.

Distortion in CMOS operational amplifier circuits

The paper presents a nonlinear distortion analysis of three basic CMOS inverter circuits, namely PMOS load, constant-current source load and push-pull inverter, and compares their performance experimentally. The analysis is based on a small-signal MOSFET model including the channel-length modulation effect. The theoretical predictions are compared with measurements made on inverters, and incorporated in an operational amplifier, fabricated in an n-well CMOS polysilicon-gate 6 μm technology. The results confirm that the distortion depends on the signal level, quiescent bias, channel-length modulation effect, device geometries and processing parameters. The push-pull inverter has higher gain and lower distortion than the other output circuits. Only third-harmonic distortion exists in the operational amplifier using the push-pull inverter as its output stage.

Application of modified Ebers-Moll model to nonlinear distortion analysis of transistor amplifiers

Application of the modified Ebers-Moll model to low-frequency nonlinear harmonic distortion analysis of transistor amplifiers is discussed. The calculated values for two types of transistor amplifiers are compared with measured values and are found to be in good agreement. Therefore the model can be used in design of low-distortion audio amplifiers.

Modified ebers-moll model

A new modified Ebers-Moll model is described. The model represents a bipolar transistor accurately in the active operating region at low frequencies. It is therefore suitable for computer-aided nonlinear distortion analysis of transistor amplifiers.

Volterra series representation of a forward-biased p-i-n diode

A nonlinear model is proposed for a forward-biased p-in diode controlled by an ac signal consisting of a group of sinusoidal signals. The model is applicable to these phases of diode operation where linearized basic physical equations are valid. Current-voltage relations have been obtained for junctions and the "i" region in the form of a Taylor series with frequency-dependent coefficients. The new model is valid for signal levels considerably exceeding those admissible for the known linear model [3], [4]. A new form of signal limiting condition, suitable for measurement verification and calculations, has been obtained. The Volterra series for the equations representing the diode has been found which correspond to the Taylor series obtained. The convergency condition for this series is identical to that for thel Taylor series. The conformability of measurement and calculation results fully testifies to the usefulness of the proposed model for nonlinear distortion analysis.

A large signal frequency domain analysis of circuits containing junction diodes and bipolar transistors

The analysis of ac circuits has been limited to either a linear approximation or slightly nonlinear distortion analysis in either of which the fundamental component of the signal can be treated as a single sinusoidal wave. If the nonlinearity is great, or in other words, if the signal is so large that it should be expressed as a Fourier series, it is necessary to consider the generation of harmonics in each term of the series, as well as all possible intermodulation products. In this paper, the analysis of a circuit containing junction diodes and bipolar transistors is shown to be possible by using a Newton algorithm to solve the equations expressing the complicated interrelation of dc, ac, and finite numbers of harmonic components. The nonlinearities of a transistor are expressed in terms of an exponential function of a diode and a diffusion capacitance, and the modified Bessel generating function is applied to express the harmonics and the intermodulation products. A transistor model in the frequency domain, expressed by these generating functions, is capable of describing the fluctuation of the dc bias point and diffusion capacitances due to ac or harmonic components, which are considered to be constant in the ordinary analysis for small signals. Branin's method [8] of dc analysis is extended to analyze circuits containing dc, ac, and harmonic components, and a further method of analysis which reduces the size of the Jacobian matrix, is also suggested.

Numerical analysis of nonlinear small-signal distortion in p-n structures

A numerical method is presented to derive the non-linear distortion of small ac signals in one-dimensional semiconducting diodes from the basic physical equations. The nonlinear input-output relations are obtained in terms of Volterra functional series. The application of this method is illustrated by computational results showing the influence of injection level on harmonic distortion and cross-modulation in p-i-n diodes. Computed values of cross-modulation are compared with measurements.

Distortion analysis of bipolar transistor circuits

In the design of long-haul analog communication systems, it is essential to understand the nonlinear distortion behavior of the electronic circuit realization. Distortion analysis of weakly nonlinear circuits has been developed based on the well-known perturbation method. In the frequency domain, the nonlinearities of a transistor are shown to be equivalently represented by intermodulation distortion sources whose amplitudes and phases are iteratively determined by the linear circuit characteristics and the Taylor-series coefficients associated with the nonlinearities. For all practical purposes, only two iterations are sufficient to yield accurate results. An algorithm for computing the second- and third-order intermodulation distortions is described. This algorithm has been implemented in a program called NODAP (nonlinear distortion analysis program). NODAP computes the smallsignal nonlinear transistor model from the recently developed integral change-control model (ICM). It then passes this information through a linear circuit analysis program for distortion computations. Computer results for several transistor circuits using Western Electric highfrequency transistors are all in excellent agreement with the measured data over a wide range of bias conditions and frequencies. This demonstrates the validity of the approach treated in the paper.

Warm-Electron Effects inn-Type Silicon and Germanium

The Boltzmann equation describing the warm-electron case is discussed and a review is given of the scattering mechanisms for $n\ensuremath{-}\mathrm{G}\mathrm{e}$ and $n\ensuremath{-}\mathrm{S}\mathrm{i}$ with relatively low doping levels. Taking into account the known band structure, the Boltzmann equation is solved by a numerical iteration method under the assumption of weak intervalley scattering. It is shown that this condition can be relaxed for special symmetry directions. The warm-electron coefficient $\ensuremath{\beta}$ has been measured in the temperature range from 77 to 250\ifmmode^\circ\else\textdegree\fi{}K by an audio-frequency method based on analysis of nonlinear distortion. Good agreement between measured and calculated results is obtained using the accepted values of the deformation-potential constants.

Nonlinear-distortion cancellation in common-base transistor amplifiers operated in the normal domain

The author's analysis of nonlinear distortion in the common-emitter (c.e.) circuit is extended to the common-base (c.b.) circuit. Noting that in the c.b. device the base current plays an insignificant role, index distortion is discarded, thus leaving only the emitter distortion and collector-loading distortion to be cancelled out. A universal design chart, independent of transistor type, is presented, to enable simple tailoring of the c.b. circuit for zero second- or zero third- or simultaneous zero second- and third-harmonic distortions.