Successive Approximation Type Research Articles

Successive approximation type resistance to digital converter

Successive approximation type direct resistance to digital converter (SAR RDC) topology is presented here. The conventional SAR type ADC is augmented with an additional opamp inverting summer and a standard resistance such that the digital output of the SAR directly indicates the value of an unknown resistance connected between the output of the digital to analog converter of the SAR RDC and the inverting input of the added inverting summer. Analysis of the proposed technique presented here helps select proper components at the design stage itself to obtain minimal errors in the measurement of the unknown resistor. The major advantage of the proposed scheme is that it retains the basic architecture of an SAR ADC and hence can be implemented with all available SAR ADC architectures, including the ability to install ‘auto-ranging’. An added advantage is that the value of the unknown resistor is determined in terms of a standard resistor and hence good accuracy is easily obtained. Simulation studies and results obtained from a prototype SAR RDC built and tested, establish the efficacy of the proffered technique. The results indicate a worst-case error of < ±0.2% and no missing codes.

Assay of direct digital output floating-wiper resistive displacement sensor

The principle of operation of a successive approximation type direct displacement to digital converter for a floating-wiper resistive potentiometric sensor, presented earlier, is analyzed in detail to ascertain possible sources of error that can affect the performance of the transducer. Based on the analysis the method is suitably modified to improve its performance. To establish the efficacy of the altered scheme, a prototype signal conditioning circuit has been built and tested using both an emulated sensor and a prototype sensor. While the worst-case error in the former was found to be 0.5%, it was less than 0.8% in the latter. The test results indicate that the digital output is directly proportional to the per-unit displacement and is independent of the value of the coupling capacitance between the floating-wiper and the resistive element.

Undiscounted Markov decision chains with partial information; an algorithm for computing a locally optimal periodic policy

In this paper we construct an algorithm of successive approximation type that computes a locally optimal periodic policy for a Markov decision chain with partial state information. The algorithm is applied to a queueing network with server control.

Plate Theories Based on Successive Higher-Order Approximation Method. 2nd Report, Numerical Examples and Accuracy Characteristics.

In this paper, static and dynamic numerical examples are presented to examine the accuracy characteristics of the theories which were formulated based on the most generalized successive higher-order approximation method in the 1st report. Simultaneously, typical successive approximation theories generalizing several previously proposed kinds of consistent theories are examined ; these were deduced by introducing some specializing assumption into the formulation method in the 1st report. From these studies, the accuracy characteristics and applicable limits of successive approximation type plate theories will be shown

A high resolution position detecting system with a SWPC for electron spectroscopy

A position sensitive single wire proportional counter (SWPC) by a charge division method has been developed for a focal plane detector of the INS π√2 iron-free β-ray spectrometer ( ϱ = 75 cm). Good position resolutions, 0.3 mm (fwhm) for electron energy higher than 200 keV and 1 mm for 40 keV electrons, have been obtained with an integral position linearity of 0.2%. Analytical expressions of the charge division mechanism for proportional counter pulses, which have a logarithmic rise, are presented. The relations between the performance parameters, which are position resolution, linearity and counting rate, and the characteristics parameters of the wire, charge amplifier and shaping network are also given. A new effect, namely that the effective counter depth becomes one-half of the actual depth, was found. This effect (half depth effect) is useful for detection of the position of low energy electrons. A new high accuracy (0.1%) and high speed (15 μs) digital divider system has been developed with the use of successive approximation type ADCs.

振幅確率密度関数測定装置用逐次比較方式A.D.C.の微分直線性改善

振幅確率密度関数測定装置用逐次比較方式A.D.C.の微分直線性改善

逐次比較方式 A. D. C. による微分非直線性を軽減したパルス波高分析手法

逐次比較方式 A. D. C. による微分非直線性を軽減したパルス波高分析手法

A monolithic 10-bit A/D using I/sup 2/L and LWT thin-film resistors

Describes the function, circuit details, and performance of a monolithic 10-bit A/D converter. The converter is a successive approximation type using linear compatible I/SUP 2/L for the SAR. The converter is completely self-contained, including both clock and voltage reference. Biasing is arranged to take advantage of naturally occurring interfaces in the circuitry, simplifying the overall circuit in comparison to discrete or hybrid approaches. The processing also includes on-chip thin-film resistors which are laser-wafer-trimmed (LWR) for overall accuracy and temperature stability. The finished circuits operate with no missing codes over the -55/spl deg/ to +125/spl deg/C temperature range.

An Electronic Systems Laboratory

This paper describes an undergraduate electronic systems laboratory which has been developed during the past year within the School of Electrical Engineering at the Georgia Institute of Technology. The objective of this laboratory is to provide the student with the opportunity to demonstrate tangibly in the laboratory the operation and interaction of discrete devices, integrated circuits, and electronic systems which he has studied or will study in the classroom. In this laboratory students perform experimentation on (a) the characteristics and applications of two basic linear ICs, the operational amplifier and anlog multiplier; (b) the operation of a successive-approximation type A/D converter and of a D/A converter; and (c) the synergistic operation of a A/D converter, D/A converter, and an operational amplifier along with other devices and subsystems to achieve a total system function. Relatively inexpensive test equipment is used which has proven quite reliable and easy to operate. Special purpose electronic system program (ESP) boards were specifically designed, constructed, and utilized to accomodate the approximately 200 students who yearly enroll in this laboratory. This paper describes the philosophy behind this electronic systems laboratory, discusses the test equipment and ESP boards utilized, and details the specific experiments performed.

Utilization of Recent Electronic Devices in Electrochemical Laboratory

The use of recent electronic devices such as linear IC (especially operational amplifiers), digital IC and various modules used to interface, are described for electrochemical applications. Those devices are treated as a ‘black box’, so that most chemists can use them as functional elements to construct various systems with no consideration of their inner principles. The present paper is divided into two parts ; the first half deals with analogue electronics and the second half with digital electronics. Analogue electronics is arranged in the following sections : 1) Analogue electronics as control elements. The basic principle of an operational amplifier is illustrated and then as an example of control use, a new electrolysis which is more general than usual chronopotentiometry or chronoamperometry is described, where the electrode potential and the current is controlled simultaneously. 2) Linear processing of analogue signals. Several simulation techniques are cited and criticized from a view point of laboratory use. CSDT (continuous space and discrete time) method and transfer function method are recommended as the simulation techniques for electrode processes. 3) Non-linear processing of analogue signals. An irreversible electode process including non-linear elements as exponential terms is cited and its simulator is given. 4) Analog switch. The principle of analogue switch is illustrated and application of it such as switching correlator and signal modulator are described. In last section of analogue electronics, promising devices such as phase-locked loop amplifier and photo-coupler as an isolator are described briefly. In digital electronics part, the importance of the knowledge for hardware is emphasized and several reasons for digitalization in measurements are interpreted. Then, the fundamentals of digital electronics are outlined briefly, assuming no previous knowledge of electronics. The operation of RS-flip-flow is given onsiderable space for understanding of the higher devices such as counters and shiftregisters. After fundamentals, digital electronics for polarographic applications are described as follows : 1) Long-period integrator for coulombmeter. The combination of V-f converter and counter is recommended as a digital coulombmeter in electrochemistry. 2) Signal generator. The use of digital IC as a signal generator is illustrated. Astable mutivibrator and monostable multivibrator are illustrated. Double-pulse generator is cited as the typical example of electrochemical use. Maximum-period signal generator is introduced as a pseudorandom signal generator. 3) Digital memory. Digital memory device for transient recording is illustrated. The device was constructed from ADC (10bit resolution and successive approximation type), DAC (10bit), MOS dynamic shift registers (10×1024 bit) and some gates for read/write control. The device was applied to electrochemical system to facilitate the correlation techniques. Typical results are illustrated. Possible use of the device is discussed. 4) Microcomputer. The use of one-chip c.p.u. for microcomputer organization isdiscussed. The possible construction of microprocesser in laboratory is described.

A 12 bit analog-to-digital converter for pulse height analysis

An ADC is described, which is of the successive approximation type and makes use of Gatti's sliding scale principle 1) for channel width averaging. The use of commercially available modular converters for both the ADC and the averager DAC resulted in a very simple and reliable construction of high stability. Conversion time is 15 μs. Differential linearity is better than 0.2%. Integral linearity is less than 0.01% and gain stability is in the order of 10 ppm/°C. A mapping of the channel profile is given for both “averager off” and “averager on”. No significant degradation of the channel profile due to the averager action could be found because of the good initial differential linearity of the ADC module.

A High-Resolution, Multiple Particle Spectrometer for the Measurement of Solar Particle Events

A particle spectrometer possessing high spectral and spatial/temporal resolution for the measurement of energetic protons, electrons and alpha particles over a broad energy and intensity range during solar particle events (SPE) was successfully launched aboard a polar-orbiting satellite on 17 October 1971. The spectrometer consists of a multi-element, silicon detector stack mounted within a plastic scintillator guard counter to form a particle telescope. The spectra of protons in the energy range 1.2-100 MeV, electrons from 0.88-1.6 MeV and alpha particles from 1.6-500 MeV are measured in four time-shared modes of operation with dual 256-channel pulse-height analyzers (PHA) of the successive-approximation type. Integral counting rates from each of the main elements of the telescope and the guard counter are measured every 32 milliseconds with low-power CMOS digital counters to provide high spatial/temporal resolution on the solar particle fluxes. Complete spectra on all three particle types over the above energy ranges are obtained every few seconds. A detailed description of the spectrometer, including a discussion of the mode logic which enhances the counting statistics in selected energy ranges, the dual pulse-height analyzers and the methods of obtaining the high temporal resolution is presented. Preliminary worldwide flight data obtained from two identical spectrometers oriented at different directions to the particle flux are also presented.