Showing papers on "Noise (electronics) published in 1994"

1/f noise sources

Abstract: This survey deals with 1/f noise in homogeneous semiconductor samples. A distinction is made between mobility noise and number noise. It is shown that there always is mobility noise with an /spl alpha/ value with a magnitude in the order of 10/sup -4/. Damaging the crystal has a strong influence on /spl alpha/, /spl alpha/ may increase by orders of magnitude. Some theoretical models are briefly discussed none of them can explain all experimental results. The /spl alpha/ values of several semiconductors are given. These values can be used in calculations of 1/f noise in devices. >

Noise as a diagnostic tool for quality and reliability of electronic devices

Abstract: Experimental facts about noise are presented which help us to understand the correlation between noise in a device and its reliability. The main advantages of noise measurements are that the tests are less destructive, faster and more sensitive than DC measurements after accelerated life tests. The following topics are addressed: 1) the kind of noise spectra in view of reliability diagnostics such as thermal noise, shot noise, the typical poor-device indicators like burst noise and generation-recombination noise and the 1/f/sup 2/ and 1/f noise; 2) why conduction noise is a quality indicator; 3) the quality of electrical contacts and vias; 4) electromigration damage; 5) the reliability in diode type devices like solar cells, laser diodes, and bipolar transistors; and 6) the series resistance in modern short channel MESFET, MODFET, and MOST devices. >

Fundamentals of interferometric gravitational wave detectors

Abstract: The search for gravitational waves the nature of gravitational waves sources of gravitational waves linear systems, signals and noise optical readout noise folded interferometer arms thermal noise seismic noise and vibration isolation design of large interferometers null instruments feedback control systems an interferometer as an active null instrument resonant mass gravitational wave detectors detecting gravitational wave signals gravitational wave astronomy prospects

Nonequilibrium fluctuation-induced transport

Abstract: Ratchetlike devices can rectify symmetric, unbiased nonequilibrium noise resulting in fluctuation-induced currents. We study some simple models to investigate the dependence of a nonequilibrium steady-state current on the characteristic features of the ratchet and the applied noise. It turns out that the magnitude and the direction of the induced current depend not only on the shape of the ratchet, but also on the statistics of the fluctuations.

1/f noise in MOS devices, mobility or number fluctuations?

Abstract: Recent experimental studies on 1/f noise in MOS transistors are reviewed. Arguments are given for the two schools of thought on the origin of 1/f noise. The consequences of models based on carrier-number /spl Delta/N or mobility fluctuations /spl Delta//spl mu/ on the device geometry and on the bias dependence of the 1/f noise are discussed. Circuit-simulation-oriented equations for the 1/f noise are discussed. The effects of scaling down on the 1/f noise is studied in the ohmic region as well as in saturation. In the ohmic region the contribution of the series resistance often can be ignored. However, in saturation the noise of the gate-voltage-dependent series resistance on the drain side plays a role in lightly doped drain LDD mini-MOST's. Surface and bulk p-channel devices are compared and the differences between n-and p-MOST's often observed is discussed. The relation between degradation effects by hot carriers or by /spl gamma/-irradiation on the one hand and the 1/f noise on the other is considered in terms of a /spl Delta/N or /spl Delta//spl mu/. Experimental results suggest that 1/f noise in n-MOST's is dominated by /spl Delta/N while in p-MOST's the noise is due to /spl Delta//spl mu/. >

Addressing substrate coupling in mixed-mode ICs: simulation and power distribution synthesis

Abstract: This paper describes new techniques for the simulation and power distribution synthesis of mixed analog/digital integrated circuits considering the parasitic coupling of noise through the common substrate. By spatially discretizing a simplified form of Maxwell's equations, a three-dimensional linear mesh model of the substrate is developed. For simulation, a macromodel of the fine substrate mesh is formulated and a modified version of SPICE3 is used to simulate the electrical circuit coupled with the macromodel. For synthesis, a coarse substrate mesh, and interconnect models are used to couple linear macromodels of circuit functional blocks. Asymptotic Waveform Evaluation (AWE) is used to evaluate the electrical behavior of the network at every iteration in the synthesis process. Macromodel simulations are significantly faster than device level simulations and compare accurately to measured results. Synthesis results demonstrate the critical need to constrain substrate noise and simultaneously optimize power bus geometry and pad assignment to meet performance targets. >

Quantum noise reduction using a cavity with a movable mirror

Abstract: When a light beam interacts with Kerr medium inside an optical cavity, its quantum fluctuations are squeezed.1 One can show that perfect squeezing can be obtained close to the turning points of the bistability curve. In order to implement such a scheme, one needs perfect Kerr media (with no losses, infinite frequency bandwidth and no excess noise) that are not available to date.2 We study here a new kind of Kerr medium, in which the nonlinearity has a mechanical origin: if a mirror is free to move, the radiation pressure will induce a coupling between its position and the intensity of the light beam, thus modifying the optical path in an intensity-dependent way.

Nonequilibrium noise and fractional charge in the quantum Hall effect.

Abstract: We study nonequilibrium edge state transport in the fractional quantum Hall regime at filling g=1/m. Tunneling of Laughlin quasiparticles between edges is shown to generate both current and voltage shot noise with a universal ratio of noise amplitudes given by (${ge}^{2}$/h${)}^{2}$. In the weak backscattering limit we predict a current shot noise satisfying Poisson statistics with charge ge, which should enable a direct measurement of the fractional charge of the quasiparticle. On resonance the quasiparticles tunnel in pairs and the effective charge entering the current shot noise becomes 2ge.

General noise analysis of nonlinear microwave circuits by the piecewise harmonic-balance technique

Abstract: This paper presents a self-consistent set of algorithms for the numerical computation of noise effects in forced and autonomous nonlinear microwave circuits. The analysis relies upon the piecewise harmonic-balance method, and thus retains all the peculiar advantages of this technique, including general-purposeness in the widest sense. The noise simulation capabilities include any kind of forced or autonomous nonlinear circuit operated in a time-periodic large-signal steady state, as well as microwave mixers of arbitrary topology. The limitations of the traditional frequency-conversion approach to noise analysis are overcome. The analysis takes into account the thermal noise generated in the passive subnetwork, the noise contributions of linear and nonlinear active devices, and the noise injected by sinusoidal driving sources of known statistical properties. The nonlinear noise models of two representative families of microwave devices (FET's/HEMT's and Schottky-barrier diodes) are discussed in detail, and several applications are illustrated. >

Adaptive photoreceptor with wide dynamic range

Abstract: We describe a photoreceptor circuit that can be used in massively parallel analog VLSI silicon chips, in conjunction with other local circuits, to perform initial analog visual information processing. The receptor provides a continuous-time output that has low gain for static signals (including circuit mismatches), and high gain for transient signals that are centered around the adaptation point. The response is logarithmic, which makes the response to a fixed image contrast invariant to absolute light intensity. The 5-transistor receptor can be fabricated in an area of about 70 /spl mu/m by 70 /spl mu/m in a 2-/spl mu/m single-poly CMOS technology. It has a dynamic range of 1-2 decades at a single adaptation level, and a total dynamic range of more than 6 decades. Several technical improvements in the circuit yield an additional 1-2 decades dynamic range over previous designs without sacrificing signal quality. The lower limit of the dynamic range, defined arbitrarily as the illuminance at which the bandwidth of the receptor is 60 Hz, is at approximately 1 lux, which is the border between rod and cone vision and also the limit of current consumer video cameras. The receptor uses an adaptive element that is resistant to excess minority carrier diffusion. The continuous and logarithmic transduction process makes the bandwidth scale with intensity. As a result, the total AC RMS receptor noise is constant, independent of intensity. The spectral density of the noise is within a factor of two of pure photon shot noise and varies inversely with intensity. The connection between shot and thermal noise in a system governed by Boltzmann statistics is beautifully illustrated. >

Dynamic analysis of radiation and side-mode suppression in a second-order DFB laser using time-domain large-signal traveling wave model

Abstract: In this paper, we have developed a relatively simple algorithm to calculate the large-signal dynamic response of DFB lasers by solving the time-dependent coupled wave equations directly in the time domain. The spontaneous emission noise, longitudinal variations of carrier (hole burning) and photon densities as well as that of the refractive index are taken into consideration. To demonstrate the power of this straightforward algorithm, the model shows how the side-mode suppression ratio in devices with high /spl kappa/L and a /spl lambda4: phase shift is significantly affected by the radiation in the second-order DFB laser. The time-dependent radiation pattern in grating-coupled surface-emitting lasers is also calculated for the first time. >

VIKING, a CMOS low noise monolithic 128 channel frontend for Si-strip detector readout

Abstract: A low noise Si-strip detector readout chip has been designed and built in 1.5 μm CMOS technology. The chip is optimized w.r.t. noise. Measurements with this chip connected to several silicon strip detectors are presented. A noise performance of ENC = 135 e− + 12 e−/pF and signal to noise ratios between 40–80, depending on the detector, for minimum ionizing particles traversing 280 300 μ m silicon has been achieved.

Optical orthogonal code-division multiple-access system .I. APD noise and thermal noise

Abstract: In an optical multiple-access system, overall system throughput efficiency add significant implementation cost-reduction would be achieved if many users could access a common optical channel at any time without control among users. Recently one such scheme, an optical orthogonal code division multiple-access system (OOCDMA), was introduced by Salehi et al. (1982) for the case of no noise. In this paper, some extensions of that work are presented, including the effects of avalanche photodiode (APD) noise and thermal noise as well as interference for the OOCDMA direct-detection receiver. Since it has been shown that an optical hard-limiter before the receiver correlator can reduce the interference effect for the OOCDMA system in the absence of noise, the hard-limiter role in the presence of thermal and APD noise is also examined. >

Current synchronous zero voltage switching resonant topology

Abstract: A power converter circuit provides low conversion losses, low generated noise and output power controllability. The circuit includes a controller, at least two transistors and an output network that provides impedance matching and operating point stabilization functions. The output network also enables zero voltage switching of the transistors, thus reducing radiated noise and minimizing (and possibly eliminating almost completely) switching losses. The controller circuitry includes an oscillator which is capable of self synchronizing to the resonant frequency of the components of the output network. Power modulation (e.g., for dimming of a lamp) is accomplished simply by desynchronizing and increasing the oscillator frequency. Thus, the control architecture allows the use of external parts of lower precision and cost while providing dimming capability in a single stage.

Thermal instability at 10 Gbit/in/sup 2/ magnetic recording

Abstract: The limitation on recording density imposed by thermal stability is systematically studied by a method combining molecular dynamics and Monte Carlo computer simulations. The thermal decay for as long as 6 months has been simulated for written di-bits at the projected anisotropy, grain size, and bit length for 10 Gbit/in/sup 2/ magnetic recording. In the presence of demagnetizing field, a single layer film has little thermal effect at the upper limit of the projected grain sizes, while thermal decay is obvious when grain sizes are at the lower limit. The magnitude of the noise peak does not change significantly while the noisy region becomes wider after thermal decay. Compared with a single layer medium of the same total thickness, a double layer film has much more serious thermal decay and the negative interaction between layers tends to demagnetize the film, therefore making the thermal effect worse. The thermal decay in multilayer media tends to cancel the gain in noise reduction obtained by dividing the film layer at ultrahigh recording density. The effects of magnetostatic and exchange interaction, anisotropy, and grain volume on thermal stability are discussed. >

Performance of Mean-Frequency Estimators for Doppler Radar and Lidar

Abstract: The performance of mean-frequency estimators for Doppler radar and lidar measurements of winds is presented in terms of two basic parameters: Phi, the ratio of the average signal energy per estimate to the spectral noise level; and Omega, which is proportional to the number of independent samples per estimate. For fixed Phi and Omega, the Cramer-Rao bound (CRB) (theoretical best performance) for unbiased estimators of mean frequency (normalized by the spectral width of the signal), signal power, and spectral width are essentially independent of the number of data samples M. For large Phi, the estimators of mean frequency are unbiased and the performance is independent of M. The spectral domain estimators and covariance based estimators are bounded by the approximate period of M. The spectral domain estimators and covariance based estimators are bounded by the approximate periodogram CRB. The standard deviation of the maximum-likelihood estimator approaches the exact CRB, which can be more than a factor of 2 better than the performance of the spectral domain estimators or covariance-based estimators for typical Omega. For small Phi, the estimators are biased due to the effects of the uncorrelated noise (white noise), which results in uniformly distributed 'bad' estimates. The fraction of bad estimates is a function of Phi and M with weak dependence on the parameter Omega. Simple empirical models describe the standard deviation of the good estimates and the fraction of bad estimates. For Doppler lidar and for large Phi, better performance is obtained by using many low-energy pulses instead of one pulse with the same total energy. For small Phi, the converse is true.

Intrinsic noise of the single-electron transistor.

Abstract: The paper is devoted to calculation of the ``classical'' (thermal and/or shot) intrinsic noise of the single-electron transistor (SET) caused by the stochastic character of electron tunneling. Exact solution of the master equation describing the dynamics of the SET is obtained in the frequency representation. The low-frequency limit for the spectral calculations is considered in detail.

Simulation techniques and solutions for mixed-signal coupling in integrated circuits

Abstract: List of Figures. List of Tables. Preface. 1. Introduction. 2. Sources of Noise and Methods of Coupling. 3. Semiconductor Device Simulation. 4. Simplified Substrate Modeling and Rapid Simulation. 5. Mesh Generation. 6. Substrate Modeling in Heavily-Doped Bulk Process. 7. Substrate Resistance Extraction for Large Circuits. 8. Modeling Chip/Package Power Distribution. 9. Controlling Substrate Coupling in Heavily-Doped Bulk Processes. 10. Controlling Substrate Coupling in Bulk P-Wafers. 11. Chip/Package Shielding and Good Circuit Design Practice. 12. A Design Example. Appendices. A: Mesh Moments. B: Convergence Behaviour of Iterative Methods. Index.

Fundamentals of low-noise analog circuit design

Abstract: This paper presents a tutorial treatment of the fundamentals of noise in solid-state analog electronic circuits. It is written for upper division students and practicing engineers who wish to gain a basic knowledge of the theory of electronic noise and techniques for low-noise circuit design. The paper presents an overview of noise fundamentals, a description of noise models for passive devices and active solid-state devices, methods of calculating the noise performance of amplifiers, and techniques for minimizing noise in circuit design. The theory and methods are applicable to both discrete and integrated circuits. >

Evading amplifier noise in nonlinear oscillators.

Abstract: Resonators driven to self-oscillation via active feedback play an important role in technology. Among the stochastic processes driving phase diffusion in such oscillators is noise from the feedback amplifier. Here a technique is described by which phase diffusion due to this noise can be suppressed. We have achieved a 10 dB reduction in phase diffusion by using the technique on an oscillator whose frequency-controlling element is a nonlinear mechanical resonator. The technique, in principle, provides a quantum nondemolition method of tracking a resonator's phase.

Generalized weighting scheme for δf particle‐simulation method

Abstract: An improved nonlinear weighting scheme for the δf method of kinetic particle simulation is derived. The method employs two weight functions to evolve δf in phase space. It is valid for quite general, non‐Hamiltonian dynamics with arbitrary sources. In the absence of sources, only one weight function is required and the scheme reduces to the nonlinear algorithm developed by Parker and Lee [Phys. Fluids B 5, 77 (1993)] for sourceless simulations. (It is shown that their original restriction to Hamiltonian dynamics is unnecessary.) One‐dimensional gyrokinetic simulations are performed to show the utility of this two‐weight scheme. A systematic kinetic theory is developed for the sampling noise due to a finite number of marker trajectories. The noise intensity is proportional to the square of an effective charge qeff=q(w/D), where w ∼δf/f is a typical weight and D is the dielectric response function.

A noise-whitening approach to multiple access noise rejection .I. Theory and background

Abstract: Minimum probability of bit error is difficult to achieve in a DS-CDMA receiver. Since multiple-access noise is the sum of many independent random processes, it is reasonable to approximate it by a Gaussian process of the same power spectral density. This leads to the criterion of maximizing signal-to-noise ratio (SNR). In this paper, receivers that maximize SNR in a particular DS-CDMA system model under various constraints are proposed and analyzed. The method proposed here does not require locking and despreading multiple arriving CDMA signals. The maximization of SNR is compared with the minimization of probability of error, when the receiver is constrained to operate bit-by-bit, in the absence of knowledge of the other users' spreading codes, timing, and phase. >

Low-frequency noise spectroscopy

Abstract: Electrical noise in excess of thermal and shot noise is caused by imperfections in the device. Its control can improve the quality of the device and its measurement can give considerable information about the nature of the defects involved. For defects with discrete energy distributions spectroscopy can be used to identify the defect and measure its properties. Excess noise has large intensity at low frequencies and several mechanisms can be identified. The value of the technique for many systems is described. Comparison is made with other methods of studying such defects. >

Traveling wave analysis of semiconductor lasers: modulation responses, mode stability and quantum mechanical treatment of noise spectra

Abstract: We present a traveling wave analysis of a general class of semiconductor lasers, which includes multisection DFB/DBR lasers and gain-coupled DFB lasers. The analysis leads to new semianalytic expressions for the small-signal IM and FM modulation responses, the intensity and FM noise spectra, and the linewidth. The expressions are given in terms of solutions to four coupled linear homogeneous differential equations and can easily be evaluated numerically. We also derive a stability parameter /spl sigma/, for which /spl sigma/ >

Optical-feedback-induced chaos and its control in multimode semiconductor lasers

Abstract: The effects of optical feedback in multilongitudinal mode semiconductor lasers are studied through computer simulations. Two separate regimes are found based on the length of the external cavity. For long external cavities (external-cavity mode spacing larger than the relaxation-oscillation frequency), the laser follows a quasi-periodic route to chaos as feedback is increased. For short external cavities, the laser can undergo both quasi-periodic and period doubling routes to chaos. When the laser output becomes chaotic, the relative-intensity noise is greatly increased (by more than 20 dB) from its solitary-laser value. Considerable attention is paid to the effects of optical feedback on the longitudinal-mode spectrum. The stabilization of the mode spectrum and the reduction of the feedback-induced noise through current modulation are studied and compared with experimental results. Current modulation eliminates feedback-induced chaos when the modulation frequency and depth are suitably optimized. This technique of chaos control has applications in optical data recording. >

Stochastic resonance in the perceptual interpretation of ambiguous figures: A neural network model.

Abstract: We describe the results of computer simulations of the dynamical behavior of an autoassociative network with a two-dimensional energy landscape. Such a network can model some aspects of the phenomenon of perceptual bistability in the presence of ambiguous figures. The network can be operated at either zero or nonzero temperatures which represent an internal system noise. Our results show that, under the influence of a weak periodic external signal, the network exhibits a maximum in the signal-to-noise ratio at an optimum noise level: the characteristic signature of stochastic resonance.

Internal fluctuations, period doubling, and chemical chaos.

Abstract: The effects of internal molecular fluctuations on period-doubling bifurcations and chaotic band merging are studied in a well-stirred reactive chemical system where spatial degrees of freedom play no role. The calculations are carried out using a stochastic model based on reactive lattice-gas cellular automata. Molecular fluctuations arising from reactive collisions are incorporated in the model and the mass-action rate equations are recovered in the mean field limit. Large system sizes can be studied and permit the investigation of the internal noise scaling structure in the periodic and chaotic regimes. For the Willamowski-R\"ossler system the noise scaling exponent is consistent with that found for one-dimensional quadratic maps subject to external noise. The model provides a means to study small, non- equilibrium, reacting systems where fluctuations may not be neglected.

A third-order sigma-delta modulator with extended dynamic range

Abstract: Oversampling modulators based on high-order sigma-delta modulation provide an effective means of achieving high-resolution analog-to-digital conversion in VLSI technology. Because high-order noise shaping greatly reduces the quantization noise in the signal band, the dynamic range of these modulators tends to be bounded by the thermal noise of the input stage and the maximum voltage swing in the signal path. This paper introduces a third-order cascaded sigma-delta modulator that uses a modified cascaded architecture and reduced gain in the first integrator to increase the dynamic range. An experimental modulator fabricated in a 1-/spl mu/m CMOS technology attains a resolution of 17 b for a 25-kHz signal bandwidth while operating from a single 5-V supply. With an oversampling ratio of 128 and a clock frequency of 6.4 MHz, the modulator achieves a 104-dB dynamic range and a peak signal-to-noise+distortion ratio (SNDR) of 98 dB. As indicated by both measurements and simulations, the cascaded architecture also greatly reduces the discrete noise peaks that can be present in a single-stage architecture. >