Showing papers in "Iete Technical Review in 1992"
TL;DR: A description of the the historical development followed by the principle of operation of the pressure transducers is given, the characteristics of an ideal pressure transducer for measurement of pressure and the general types of pressure Transducer are given.
Abstract: Pressure transducers find wide spread usage for a variety of applications. In this article, a description of the the historical development followed by the principle of operation of the pressure transducers is given. The characteristics of an ideal pressure transducer for measurement of pressure and the general types of pressure transducer are also given. After description of these basic concepts, the remaining part of the paper is devoted to the various steps involved in the design and fabrication of the pressure transducer. The typical data and performance of the transducer developed are also included. The paper ends with the description on the latest development of pressure transducers viz, the thin film pressure transducers.
9 citations
TL;DR: An overview of the Walsh analysis with special stress upon its application in the fields of communication, systems, control and other areas as well is given.
Abstract: The piecewise constant Walsh function is not new in the field of mathematics because it was proposed in the year 1923 by J L Walsh. But its suitability to qualify as an elegant mathematical tool for the analysis of physical systems became apparent to the researchers quite late. Though other functions of the same piecewise constant orthogonal class attracted attentions of scientists as well as technologists to find frequent applications, the Walsh function has maintained its leadership among its clan having wide application areas ranging from the field of communication to the area of systems and control. The applications encompass die areas of digital signal processing image processing, logic circuit design etc.The present paper gives an overview of the Walsh analysis with special stress upon its application in the fields of communication, systems, control and other areas as well. The paper also reviews other non-sinusoidal orthogonal functions of the same class. Considering the present state of applicatio...
5 citations
TL;DR: In this paper, the electrode shapes for an axially symmetric gridded convergent Pierce electron gun were determined by solving Laplace/Poisson's equations subject to specified boundary conditions.
Abstract: The determination of electrode shapes for an axially symmetric gridded convergent Pierce electron gun involves solution of Laplace/Poisson's equations subject to specified boundary conditions. Finite element and iterative techniques are used for this purpose. The functional for this is calculated with the use of Laplace's equation in the form of two dimensional axially symmetric spherical co-ordinates. The electrode shapes are determined with the use of this functional and appropriate boundary conditions. A computer program is developed for this purpose and the resulting electrode shapes for a typical gridded electron gun are presented. The effects of variation of input parameters on the electrode shapes are also shown.
5 citations
TL;DR: The basic design of a TWT is obtained in stages for the given design parameters in respect of bandwidth (BW), gain, output power, efficiency, signal to noise ratio, and AM-to-PM conversion coefficient using analytical methods or available database.
Abstract: The basic design of a TWT is obtained in stages for the given design parameters in respect of bandwidth (BW), gain, output power, efficiency, signal to noise ratio, and AM-to-PM conversion coefficient using analytical methods or available database. The final design is achieved by optimization, using computer-aided design (CAD) packages for individual sections.Generally, one may choose to first proceed with the design of slow-wave structure (SWS). The type and geometry of SWS is decided by the dispersion, which decides the BW, and interaction impedance, which decides the gain. Initial estimates of helix radius and pitch are first made on the basis of helix voltage and dielectric loading factor. At the initial stage, small signal model is used to check the parameters of the SWS, which are then optimized using the large signal model of beam-wave interaction.In the second stage, the basic design of electron gun is carried out using simple Pierce synthesis techniques. This is then optimised using electron gun ...
4 citations
TL;DR: A new dispersion relation for a dielectric loaded tape helix in an anisotropically conducting metal shell has been developed to include the effect of spatial harmonics and it has been established that the number of forbidden zones appearing in dispersion characteristics of a structure is equal to the number-of- forbidden zones taken into consideration.
Abstract: A new dispersion relation for a dielectric loaded tape helix in an anisotropically conducting metal shell has been developed to include the effect of spatial harmonics. It has been established that the number of forbidden zones appearing in dispersion characteristics of a structure is equal to the number of spatial harmonics taken into consideration. Also, a comparison has been made between the dispersion results of tape helix model and those of sheath helix model for typical structures.
4 citations
TL;DR: In this paper, a transducer system for hyperthermia applications is described, where a plano-concave perspex lens on the front surface of the transducers is used to focus the ultrasound beam.
Abstract: A transducer system is described for hyperthermia applications. By changing only mechanical attachments, it is possible to have the system to function at different frequencies (0.5–3 MHz). Focusing of the ultrasound beam is achieved by a plano-concave perspex lens on the front surface of the transducer. A mechanical arrangement is used to change the lens and the disc to provide focal lengths ranging between 90–150 mm at different frequencies and intensities from the same transducer system.
3 citations
TL;DR: The Petri Net (PN) model of computer control system has been developed to provide total real-time tasks and the execution sequence and their interactions and the experimental results have been provided to obtain optimal controller parameters using reaction curve as well as quarter amplitude damping.
Abstract: The paper presents real-time software design methodology and control of liquid-level system using a microcomputer. Basic principles of data acquisition, actuators characterization, computer interfacing with sensors/actuators, and controller tuning of the unknown process model have been discussed. The experimental setup consists of a water tank, capacitance type level sensor and a stepper motor driven needle control valve. The level sensor and stepper motor are interfaced with an IBM compatible PC/XT which has been programmed in TURBO PASCAL Ver 5.0+ to record and control the water level in the tank. The Petri Net (PN) model of computer control system has been developed to provide total real-time tasks and the execution sequence and their interactions. The experimental results have been provided to obtain optimal controller parameters using reaction curve as well as quarter amplitude damping. The closed-loop response is obtained to show the effectiveness of the design methodology.
2 citations
TL;DR: The past decade has seen the emergence of computer networks as an indispensable tool in interpersonal and intersystem communications as more and more people have begun to use networks the size of the networks and their users have also increased greatly.
Abstract: The past decade has seen the emergence of computer networks as an indispensable tool in interpersonal and intersystem communications. As more and more people have begun to use networks the size of the networks and their users have also increased greatly. As networks grow bigger and bigger, the volume of information to be remembered by users and applications increase. This gives rise to the need for a common repository of information which can be accessed through the network.Such a common repository of information can be realized by means of the Directory. The Directory is an application that holds and provides access to information about objects in the real world. An object is anything that can be named, ranging from humans to application processes, and devices. The Directory will provide user-friendly names for objects. It will be typically used to facilitate communication between objects such as application entities, people, etc. Realizing the importance of the Directory, a detailed study on the various...
2 citations
TL;DR: In this article, the progress of the electron gun design, limiting to axially symmetric geometries, is discussed with a view to utilise such guns for electron accelerators, and the mechanical design features leading to the physical configuration of the gun with stringent tolerances are outlined.
Abstract: The progress of the electron gun design, limiting to axially symmetric geometries is discussed here with a view to utilise such guns for electron accelerators. The mechanical design features leading to the physical configuration of the gun with stringent tolerances are outlined. Vacuum processing is done at pressures of 1.3 × 10−7 Pa. The gun employs W-filament emitter or a cathode pellet with bombarder service. A water cooled compact faraday cup is used to measure the electron current. Electron gun geometries have been studied using the computer programme. The perveance of the gun is 0.7 × 10−7 A/V1.5 at 80 kV. Developmental techniques of such pulsed electron guns are described.
2 citations
TL;DR: The Electron Cyclotron Resonance (ECR) ion sources are finding prominant role in recent times, because of their higher beam current producing capability than the conventional ion sources.
Abstract: Microwave technology is widely employed for accelerating electrons in accelerators such as Linac and Microtron. These accelerators have found applications as follows (i) Linear collider, (ii) Radiotherapy, (iii) X-ray radiography, and (iv) Free electron laser. The advantages of using microwave (S-band) in the above accelerators are discussed with their operating principle. The theory and experimental aspects pertaining to cavities as well as different configurations involved in microwave feed structure for coupling microwave from source to cavities are described. The microwave source requirement for different types of Linac and Microtron is also presented.The Electron Cyclotron Resonance (ECR) ion sources are finding prominant role in recent times, because of their higher beam current producing capability than the conventional ion sources. These modern sources are used in Tandem mirror, Cyclotron, Proton Linac and Implanter. The microwave theory and technological aspects involved in ECR ion sources are di...
2 citations
TL;DR: The rain rate distributions deduced from rapid response rain gauge measurements over different locations in India are presented from the point of view microwave attenuation by rain to obtain a power law of rain fall rate.
Abstract: The rain rate distributions deduced from rapid response rain gauge measurements over different locations in India are presented in this paper from the point of view microwave attenuation by rain. Based on the simultaneous observations of rain fall rate measured by rain gauges having integration times 10 seconds and 15 minutes, a power law has been obtained. The extension of rain cells deduced from radiowave attenuation data is found to be dependent on rain rate.
TL;DR: The details of the generated output from the large signal models for helix and coupled-cavity TWTs and how such outputs can be interpreted for analysing the performances of different types of TWTs are described.
Abstract: One-dimensional large signal (nonlinear) models for coupled-cavity and helix travelling wave tubes (TWTs) were developed. These models are at least 5 to 6 times faster than the other known large-signal models with no loss in accuracy and present detailed description of the rf circuit field and modulated beam characteristics along a tube and at the output, in both tabulated and graphical forms. This paper describes the details of the generated output from the large signal models for helix and coupled-cavity TWTs and how such outputs can be interpreted for analysing the performances of different types of TWTs.
TL;DR: A Strategy for Electronics Development in India: Design and Technology Innovation as discussed by the authors, 1992, Vol. 9, No. 5, pp. 329-333; IETE Technical Review: Vol.
Abstract: (1992). Design and Technology Innovation: A Strategy for Electronics Development in India. IETE Technical Review: Vol. 9, No. 5, pp. 329-333.
TL;DR: In this paper, the authors used the technique of pulse echo measurement and operate in a similar manner as sonar, where a pulse of energy is transmitted from the probe and travels through the media to the far side where it is reflected back.
Abstract: The ultrasonic instruments employ the technique of pulse echo measurement and operate in a similar manner as sonar. A pulse of energy is transmitted from the probe and travels through the media to the far side where it is reflected back. The time between the transmit pulse and first echo is measured. During this travel time, due to the physical properties of media, amplitude of the echo is reduced and errors are introduced in the thickness measurements. The ultrasonic pulse also produces the thermal effect and changes the velocity of the waves. Various techniques are given to overcome these problems in case of thickness measurement using ultrasonic instruments.
TL;DR: The history of progress regarding microwave amplifiers and generators is presented and special emphasis is laid on the specification of various physical principles underlying new varieties of generators and amplifiers.
Abstract: The history of progress regarding microwave amplifiers and generators is presented. Besides the influence of advances in tube technology and circuit techniques, special emphasis is laid on the specification of various physical principles underlying new varieties of generators and amplifiers. The physical concepts are only depicted in their essentials and familiarity with microwave tubes is assumed.
TL;DR: In the present investigation, a new technique based on focused ultrasound has been tried for the disintegration of kidney or gall bladder stones.
Abstract: The presence of calculi in any part of the body cause pain and discomfort to the patient. In the present investigation, a new technique based on focused ultrasound has been tried for the disintegration of kidney or gall bladder stones.
TL;DR: Two variants of six-component balance configurations, strain gauge installation procedure, thermal performance, typical calibration and operational of strain-gauge balance in wind tunnel test applications are described.
Abstract: Aerodynamic forces and moments acting on scaled models of aircraft and missiles are generally measured by a multi-component transducer called the ‘Internal Strain Gauge Balance.’ This multi-component transducer which fits inside the model, incorporates six specially machined elements to measure three components of forces and three components of moments on the model. The air loads on the elements appear as strain, which is measured by resistance strain gauge transducers. The paper describes two variants of six-component balance configurations, strain gauge installation procedure, thermal performance, typical calibration and operational of strain-gauge balance in wind tunnel test applications.
TL;DR: Several techniques of analysis of underwater acoustic transducers range in complexity from the simple one used to obtain an approximate value of the resonance frequency by using impedance transformation concepts to the numerical models which can be used to accurately predict even stress levels in all parts of the transducer.
Abstract: Several techniques of analysis of underwater acoustic transducers are briefly overviewed. These techniques range in complexity from the simple one used to obtain an approximate value of the resonance frequency by using impedance transformation concepts to the numerical models which can be used to accurately predict even stress levels in all parts of the transducer. The evolution of techniques, their limitations and the reasons for using the more complex ones are highlighted keeping sonar transducers in mind.
TL;DR: An all-digital bidirectional code converter between 64 kbps standard PCM and 32 kbps CVSD encoded signals has been developed using a Texas Instrument's floating point DSP chip TMS320C30.
Abstract: An all-digital bidirectional code converter between 64 kbps standard PCM and 32 kbps CVSD encoded signals has been developed using a Texas Instrument's floating point DSP chip TMS320C30. This paper describes the design, implementation and performance issues including compatibility to existing PCM and CVSD codecs.
TL;DR: In this article, the Mean-Time-To-Failure (MTOF) of a resistor is strongly related to environmental and operational stresses and the type of component, and it appears from the result that the mean-time-to-fail (reciprocal of failure rate) of resistor is highly correlated with type of resistor.
Abstract: Laboratory and field exposure studies, under different environmental and operational stresses, are carried out to evaluate the life of electronic components. Fixed resistors (carbon film, metal oxide and metal film type) have been used for investigations. Test duration varies from 14500 to 28500 hrs. Toe performance degradation and/or failure is a result of stress on the component. It appears from the result that the Mean-Time-To-Failure (reciprocal of failure rate) of resistor is strongly related to environmental and operational stresses and the type of component.
TL;DR: In this paper, the authors discuss CS01, CS02, CE01, CE03, RE02 and RS03 test requirements of MIL-STD-461/462 and show that compliance to these standards leads to over design in general.
Abstract: The paper briefly discusses CS01, CS02, CE01, CE03, RE02 and RS03 test requirements of MIL-STD- 461/462. It shows that (i) compliance to these standards leads to over design in general, (ii) narrow...
TL;DR: The efficacy of enhancing the efficiency of helix TWT using velocity taper using the DDM model is described and some of the aspects of the design are brought out.
Abstract: The efficacy of enhancing the efficiency of helix TWT using velocity taper is described. An ideally designed velocity taper can result in a 50% increase in efficiency. However, there are practical problems in achieving such high efficiencies in high power, broadband TWTs when dynamic velocity tapers are to be included. The design of these methods require large signal computer analysis and the present analysis is based on the DDM model. This paper brings out some of the aspects of the design.
TL;DR: In this paper, the effect of deformation elevation has been analyzed and it has been found that the elevation of the order of 45° yields the maximum power for the case when the deformation is introduced at 90% of the interaction region.
Abstract: It has been observed that on approximate geometrical deformation introduced in a given cavity capable of generating power further enhances its power generating capability. The present paper deals with the development of a theoretical expression for the enhanced power. The expression has shown that power is maximum for the case when the deformation is introduced at 90% of the interaction region. The effect of deformation elevation has been analysed. It has been found that the elevation of the order of 45° yields maximum power.
TL;DR: The paper deals with TTL, CMOS, STTL and HCMOS digital logic devices for their functional characteristics towards HF, VHF and UHF frequencies and reports the uncertain characteristics of the gates at the transition region.
Abstract: The paper deals with TTL, CMOS, STTL and HCMOS digital logic devices for their functional characteristics towards HF, VHF and UHF frequencies. It has been identified that commonly used logic devices provide a very high gain RF coupling path particularly when used as terminal devices in data transmission lines. The uncertain characteristics of the gates at the transition region have been reported in this paper. Useful data concerning RF threshold levels, RF gain at the transition state for the logic families are included. Various methods to control the unwanted RF gain of these devices and their implications on the basic characteristics have been studied and also reported. The result of analysis can be used in the selection and application of these devices in strategic areas of data communication and signal processing.
TL;DR: In this article, the authors enumerated the potential types of biosensors, their applications and an ever-increasing demand for research on development of biosensor has been enumerated in this paper.
Abstract: All sectors of human endeavour require novel development of cheap and simple devices for acquiring relevant analytical information in short duration. Emphasis is been laid on estimation, in-situ monitoring and control of chemical species in environmental and biotechnological processes. Research in the field of biosensor is likely to have a significant impact on development of modern electronics and in-situ monitoring of molecular species. In view of this potential types of biosensors, their applications and an ever-increasing demand for research on development of biosensors has been enumerated in this paper.
TL;DR: A low cost, microprocessor-based multiparameter measurement system capable of making automated measurements of in-circuit, discrete and incremental resistances and capacitances with high degree of accuracy and over a wide range of parameter values is given.
Abstract: In this paper, the realization and design of a low cost, microprocessor-based multiparameter measurement system is given. It is capable of making automated measurements of in-circuit, discrete and incremental resistances and capacitances with high degree of accuracy and over a wide range of parameter values. The system employs two R- and C-composite modules, which respectively give output voltages linearly proportional to the resistance or capacitance under consideration. This analog output voltage is digitized, calibrated and displayed on six 7-segment displays, along with the units. Experimental results on parameter measurements are in conformity with the theory. The system has the attractive feature of being, insensitive to the signal frequency.
TL;DR: In this article, a demountable electrostatic module for secondary electron emission (SEE) ratio measurement has been developed and tested using a narrow angle electron gun and a cylindrical collector to collect emitted secondaries.
Abstract: In this paper, the design and development of a simple demountable electrostatic module for measuring Secondary Electron Emission (SEE) ratio have been given. SEE ratios of metals and thin film metal oxides have been successfully measured. The module consists of a narrow angle electron gun, which is the source of primary electron beam of wide energy range, and a cylindrical collector to collect emitted secondaries. Design procedure for the electron gun in particular and module in general have been described. Computer plots of equipotentials and electron trajectories are shown. The validity of SEE measurements using the module has been established using platinum as standard. It has been observed that the module reliably measures SEE ratios for beam voltages ranging between 100 V and 3.6 kV and with little modification its range can be extended down to voltages less than 100 V.
TL;DR: The external quality factor of a dielectric resonator placed on a dieLECTric spacer and coupled to a microstrip line in TE01δ mode is evaluated using the concept of image current.
Abstract: The external quality factor of a dielectric resonator placed on a dielectric spacer and coupled to a microstrip line in TE01δ mode is evaluated using the concept of image current. Theoretical and experimental results are presented for a 9 GHz dielectric resonator.