1-V rail-to-rail operational amplifiers in standard CMOS technology

The constraints on the design of CMOS operational amplifiers with rail-to-rail input range for extremely low supply voltage operation, are addressed. Two design approaches for amplifiers based on complementary input differential pairs and a single input pair, respectively, are presented. The first realizes a feedforward action to accommodate the common-mode (CM) component of the input signals to the amplifier input range. The second approach performs a negative feedback action over the input CM signal. Two operational amplifiers based on the proposed approaches have been designed for 1-V total supply operation, and fabricated in a standard 1.2-μm CMOS process. Experimental results are provided and the corresponding performances are discussed and compared     

Consensual and Hierarchical Classification of Remotely Sensed Multispectral Images

Consensual and hierarchical approaches are developed for the classification of remotely sensed multispectral images. The proposed method consists of preprocessing of input patterns, generating multiple classification results by hierarchical neural networks, and a combining scheme to generate a consensus of multiple classification results. Transformations of input patterns by random matrices and nonlinear filtering are used for preprocessing. By varying the input patterns, the multiple classification results are generated with sufficiently independent errors by using a single type of classifier. This helps to improve classification performance when the multiple classification results are combined. Hierarchical neural networks involve the use of successive classifiers which are tuned to reduce the remaining errors to increase the classification performance. This structure includes detection schemes to decide whether successive classifiers are utilized for each input. Consensual and hierarchical approaches generate more reliable and accurate results based on group decision.     

Performance analysis of LMS adaptive prediction filters

The conditions required to implement real-time adaptive prediction filters that provide nearly optimal performance in realistic input conditions are delineated. The effects of signal bandwidth, input signal-to-noise ratio (SNR), noise correlation, and noise nonstationarity are explicitly considered. Analytical modeling, Monte Carlo simulations and experimental results obtained using a hardware implementation are utilized to provide performance bounds for specified input conditions. It is shown that there is a nonlinear degradation in the signal processing gain as a function of the input SNR that results from the statistical properties of the adaptive filter weights. The stochastic properties of the filter weights ensure that the performance of the adaptive filter is bounded by that of the optimal matched filter for known stationary input conditions     

Granular quantization noise in the first-order delta-sigmamodulator

A unified approach to analyzing the granular quantization error of the first-order ΔΣ modulator is presented. The approach handles many of the previously analyzed input sequences in addition to a large class of new input sequences. By averaging over the arbitrarily small amount of circuit noise assumed to be present at the analog input to the ΔΣ modulator, a simple expression for the autocorrelation of the quantization error is derived. Each term in the expression is formally equal to the quantization error of a nonoverloaded uniform quantizer operating upon a finite partial sum of consecutive input sequence samples. Hence, existing results concerning uniform quantizers are directly applicable in evaluating the autocorrelation expression for specific input sequences. The theory is also applicable to deterministic input sequences, and has been applied to obtain a new closed-form result for sinusoidal input sequences. Ergodic results which assert that, under mild conditions, the autocorrelation equals the time-average autocorrelation in probability are presented     

Calculated admittance of an idealized drill rod antenna in a lossy medium

Some calculated results for the input admittance of both insulated and uninsulated drill rods immersed in a lossy medium are given. The source can be either a voltage gap or a thin toroidal coil. For this input admittance calculation the drill rod is assumed to be of infinite length. Even a very thin insulating layer is found to greatly decrease the real part of the input admittance or the input power.     

Optical polarization bistability in TM wave injected semiconductorlasers

Experimental results of optical polarization bistability in InGaAsP lasers are reported and the causes of polarization switching and nonlinear response in this bistability are discussed. The input light signal consisted of the transverse magnetic (TM) wave, while the semiconductor lasers operated in a fundamental transverse electric (TE) mode when the light input was not injected. The light output versus light input characteristics were dependent on the input wavelength. Switching times of up to a few hundred picoseconds were achieved for both switch-up and switch-down. It was found that the TE and TM outputs originate from the TE oscillation and the TM amplification, respectively. Calculations using the rate equations showed that the TM input induces the nonlinearity of the carrier density. These results indicate that this bistability is a type of dispersive bistability     

Interleaved three-phase boost rectifiers operated in thediscontinuous conduction mode: analysis, design considerations andexperimentation

Interleaved discontinuous conduction mode (DCM) three-phase boost rectifiers provide current ripple cancellation and increase the effective frequency of the input current ripple. As a result, the size and cost of the differential mode (DM) input filter is reduced. This work presents a detailed analysis of the input current ripple of interleaved three-phase DCM boost rectifiers. The design curves derived from the analysis are used to determine the DM input filter parameters. The experimental results are shown for two interleaved three-phase DCM boost rectifiers rated at 8 kW of total power and operated at 40 kHz with IGBTs as the main power switches. The results show that the interleaved rectifiers comply with the IEC 61000-3-2 Class A harmonic standard for this power level     

On input impedance of an arbitrarily oriented small loop antenna in a cold collisionless magnetoplasma

Closed-form expressions are derived for the input impedanceZof a small loop antenna with arbitrary orientation in a cold collisionless uniform multicomponent magnetoplasma. The closed-forms results ofZare compared with numerical results from a full-wave formal solution. It is found that for small loops these approximate formulas adequately represent the loop input impedance.     

Convergence behavior of affine projection algorithms

A class of equivalent algorithms that accelerate the convergence of the normalized LMS (NLMS) algorithm, especially for colored inputs, has previously been discovered independently. The affine projection algorithm (APA) is the earliest and most popular algorithm in this class that inherits its name. The usual APA algorithms update weight estimates on the basis of multiple, unit delayed, input signal vectors. We analyze the convergence behavior of the generalized APA class of algorithms (allowing for arbitrary delay between input vectors) using a simple model for the input signal vectors. Conditions for convergence of the APA class are derived. It is shown that the convergence rate is exponential and that it improves as the number of input signal vectors used for adaptation is increased. However, the rate of improvement in performance (time-to-steady-state) diminishes as the number of input signal vectors increases. For a given convergence rate, APA algorithms are shown to exhibit less misadjustment (steady-state error) than NLMS. Simulation results are provided to corroborate the analytical results     

Analysis of stacked microstrip patches with a mixed potentialintegral equation

A method based on the mixed potential integral equation for the analysis of flat microstrip antennas in a double-layer substrate is presented. The method is used to compute the input impedance of a stacked patch configuration. This structure permits a larger bandwidth and may also provide dual-frequency operation. The Green's functions are discussed in detail, and numerical results are obtained for the propagation constant of the dominant surface wave. Theoretical and experimental results are compared for a dual-frequency and a broadband stacked patch antenna. Theoretical results for the input impedance are in good agreement with measurements. The difference between theoretical and experimental results for the resonant frequency is less than 4.5% in all cases     

Reduction of the input current harmonic content in matrixconverters under input/output unbalance

This paper deals with the performance evaluation of space-vector-modulated matrix power converters under input and output unbalanced conditions. Two control strategies of the input current displacement angle are presented and compared in order to emphasize their influence on the input current harmonic content. The first is based on keeping the input current vector in phase with the input voltage vector. In the second, the input current displacement angle is dynamically modulated as a function of positive- and negative-sequence components of the input voltages. In both cases, the harmonic content and the three-phase RMS value of the input current have been evaluated analytically. The input current harmonic spectrum is quite different for the two control strategies and can be related to the input and output unbalance. It has been verified that, in the usual case of balanced output conditions, using the second method, it is possible to eliminate the harmonic components of the input current. Some numerical simulations are presented to confirm the analytical results     

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     

Harmonic and Intermodulation Performance of Metallic Carbon Nanotube (MCNT) and Complementary Carbon Nantube Field Effect Transistor (CNTFET) Amplifier

This paper presents a simple mathematical model for the output-voltage (current)/ input-voltage characteristic of the carbon nanotube field effect transistor (CNTFET) complementary inverting amplifier and the metallic carbon nanotube (MCNT) interconnect. The model, basically a Fourier series, yields closed-form expressions for the amplitudes of the harmonic and intermodulation components of the output voltage (current) resulting from a multisinusoidal input voltage. The special case of a two-tone equal-amplitude input voltage is considered in detail. The results show that the harmonic and intermodulation performance of the complementary CNTFET-based inverting amplifier and the MCNT interconnect is strongly dependent on the values of the amplitudes of the input tones with the third-order intermodulation component dominating over a wide range of the input voltage amplitudes. The results also show that while the harmonics may exhibit minima, the intermodulation products are almost monotonically increasing with the increase in the input voltage amplitude and exhibit no minima.     

Theoretical performance of the capacitor-diode voltage multiplierfed by a current source

The theoretical performance of the capacitor-diode voltage multiplier (CDVM) with impressed current input and constant voltage output is studied. The operating modes of the CDVM are described, and expressions for the voltages and currents are derived for the incomplete configuration. The results are immediately extended to any input waveform. The case of sinusoidal current input is fully characterized, giving useful design expressions     

A method of moments analysis and a finite-difference time-domainanalysis of a probe-sleeve fed rectangular waveguide cavity

A multifilament method of moments (MOM) analysis and a finite-difference time-domain (FE-TD) analysis are used to numerically calculate the input impedance of a probe-sleeve fed rectangular waveguide which has been short-circuited on one side. The input impedance of the system is determined by using the above methods for several probe-sleeve configurations, and reasonable agreement between the two methods for the cases studied is found. An MOM Green's function formulation which is based on scattering superposition and which allows the input impedance of a probe-sleeve feed to be calculated when the waveguide is terminated in a given load is derived. The MOM results and FD-TD numerical results are compared for this loaded waveguide input impedance case, and reasonable agreement between the methods is found. A comparison of theory and experiment is given for when the waveguide is terminated in a ground plane aperture     

Average level crossing rate and average fade duration of selectiondiversity

The average level crossing rate and average fade duration of the output signal envelope of a selection diversity combiner, operating on independent, but nonidentical fading input branch signals are derived. The exact closed-form results are valid for arbitrary diversity order, and are obtained for Rayleigh, Ricean, and Nakagami fading input signals     

On the almost sure rate of convergence of linear stochastic approximation algorithms

The almost sure rate of convergence of linear stochastic approximation algorithms is analyzed. As the main result, it is demonstrated that their almost sure rate of convergence is equivalent to the almost sure rate of convergence of the averages of their input data sequences. As opposed to most of the existing results on the rate of convergence of stochastic approximation which cover only algorithms with the noise decomposable as the sum of a martingale difference, vanishing and telescoping sequence, the main results of this paper hold under assumptions not requiring the input data sequences to admit any particular decomposition. Although no decomposition of the input data sequences is required, the results on the almost sure rate of convergence of linear stochastic approximation algorithms obtained in this correspondence are as tight as the rate of convergence in the law of iterated logarithm. Moreover, the main result of this correspondence yields the law of iterated logarithm for linear stochastic approximation if the law of iterated logarithm holds for the input data sequences. The obtained general results are illustrated with two (nontrivial) examples where the input data sequences are strongly mixing strictly stationary random processes or functions of a uniformly ergodic Markov chain. These results are also applied to the analysis of least mean square (LMS) algorithms.     

Input Impedance of Coaxial Line to Circular Waveguide Feed

The expressions for the real, imaginary parts of the input impedance seen by a coaxial line driving a thin cylindrical probe in a dominant TE/sub 11/ mode circular waveguide are derived. The analysis is carried out by assuming that the cylindrical post is replaced by a curvilinear strip having maximum width equal to the diameter of the probe. Theoretical results on input VSWR and input impedance seen by a coaxial line are in close agreement with experimental data.     

Prediction of Gain Expansion and Intermodulation Performance of Nonlinear Amplifiers

A mathematical model for the input‐output characteristic of an amplifier exhibiting gain expansion and weak and strong nonlinearities is presented. The model, basically a Fourier‐series function, can yield closed‐form series expressions for the amplitudes of the output components resulting from multisinusoidal input signals to the amplifier. The special case of an equal‐amplitude two‐tone input signal is considered in detail. The results show that unless the input signal can drive the amplifier into its nonlinear region, no gain expansion or minimum intermodulation performance can be achieved. For sufficiently large input amplitudes that can drive the amplifier into its nonlinear region, gain expansion and minimum intermodulation performance can be achieved. The input amplitudes at which these phenomena are observed are strongly dependent on the amplifier characteristics.     

Energy consumption in RC tree circuits

In this paper, resistance-capacitance (RC) tree networks are modeled in terms of their energy consumption associated with an input transition. This work significantly extends the results that the same authors previously obtained in the specific case of ladder networks with only ramp signals. The proposed approach to model the energy consumption is based on a single-pole approximation, in which an equivalent time constant is analytically derived from an exact analysis for very slow and very fast input transitions. The model is then extended to arbitrary values of the input rise time by exploiting some intrinsic properties of RC tree networks. The approach is completely analytical and leads to closed-form results. Analytical results are explicitly derived for different inputs, such as the ramp and the exponential waveforms which are usually encountered in current VLSI circuits, as well as the saturated sine input. Due to its simplicity, the proposed energy expression is suitable for pencil-and-paper evaluation and allows for an intuitive understanding of the network dissipation. The energy expression proposed is shown to be accurate enough for modeling purposes through comparison with SPICE simulations.