Interface Logic Research Articles

Broadcasting and Standard Time and Frequency Dissemination

All India Radio has been rendering time dissemination service right from its inception and presently it broadcasts time signal pips almost on an hourly basis from 0600 to 2300 hours I.S.T. on medium and shortwave frequencies. In order to improve the accuracy of these time signal pips, Research Department of All India Radio in collaboration with National Physical Laboratory, New Delhi developed a solid state, interface logic unit for use with Caesium Atomic Clock for synchronization of AIR time signal pips.In India, NPL, New Delhi disseminates standard time and frequency information under the call sign ‘ATA’ on 5,10 and 15 MHz frequencies. In order to assess the reception of ATA/NPL transmissions in India, AIR had conducted monitorings of these broadcasts and results were reported. The predicted field strength values have been found to agree fairly well with the observations. However, these investigations were based on very limited monitorings made at a few locations in India. Recently, AIR again conducted...

A general purpose 1024-stage electronically programmable transversal filter

The architecture, design, and performance of a filter implemented in CCD/NMOS technology is described. The device features programmability of the reference signal, the filter length, and weighting coefficient resolution. Off-chip circuitry is minimized by incorporating both analog and digital support circuitry, such as clock logic, drivers, amplifiers, and microprocessor interface circuitry on chip. This results in a monolithic analog signal processing system that has the flexibility to be operated in nine programmable configurations, from 1024 stages by 1 bit, to 128 stages by 8 bits. The versatility of the device makes it suitable for a wide range of applications, from matched filtering with chirp signals and very long binary sequences, to image correlation and chirp signals and very long binary sequences, to image correlation and programmable filtering.

The Development of a Bubble Memory Controller for Low-Cost FiIe Use

The bubble memory has several features such as low-cost low-power consumption, small physical size, high reliability, and non-volatility, which make it suitable for low-cost microcomputer files. The microcomputer interface and bubble control logics are integrated into a single chip which we call the bubble memory controller (BMC), making it possible to install a complete 1 Mbit bubble memory system on a 15 cm X 18 cm board. This paper describes in detail the BMC development and considers important matters in the design of large-scale logic LSI's which are represented by the microprocessors.

A microprocessor-based semi-automatic apparatus for measuring high impedances in the low and very low frequency range

The problems of long experimental duration have been solved by the realisation of a semi-automatic apparatus. A microprocessor-based logic interface makes possible data transfer from a frequency response analyser to a numerical calculator tape. Experiment control, data transfer and storage, further mathematical treatments and plotting of diagrams are performed by this system. A detailed description of the interfacing circuitries is given.

Simulating modular microcomputers

Detailed logic design followed by breakboarding of microprocessor-based systems makes development costly. This paper reports on the use of a high-order language for designing simulation models of microcomputer functional elements ("macromodules") at the register level and for verifying the timing and interface requirements for a family of microcomputer configura tions. The definitions of these microcomputer macro modules (i.e., microprocessors, memories, and input/ output interface modules) was derived in previous system analyses and simulation work reported in References 1 through 5, which were sponsored by the Office of Naval Research. Of the several simulation or emulation methods avail able for studying the design of computer architecture, the technique adopted here provides the level of simulation required to verify timing, interface logic, and data flow within and between macromodules in the family for subsequent simulations of system performance. Furthermore, module-level simulation using discrete logic forms the necessary link between system design and the ultimate description of hardware for a low cost, step-by-step design process. Writing and executing the module simulation programs provides a disciplined approach to hardware design, since the components have to be modeled in detail to follow the flow of data and timing in a microcomputer. The modeling was done in a register-transfer language called Computer Design Language, which is very con venient for this kind of simulation model. Examples of programs in CDL are included.

The application of a number-oriented microprocessor to real-time data processing

The application of a National MM57109 microprocessor to low energy stopping cross-section measurement is described. The circuit interface logic and microprocessor capabilities required for the above application are reviewed.

V-M.O.S. improves efficiency through switching performance

Since the first commercially available 2 A V-metal-oxide-semiconductor (V-m.o.s.) transistor in late 1975, development has been continued by Siliconix and others to extend the current and voltage capabilities of V-m.o.s. and other m.o.s. power structures, which will enable a wider range of application to be achieved in future, especially in the fields of power conversion and motor control. Lower current devices will also be required for general logic interface and signal switching applications, and these areas are not being neglected

The TMC 0280 speech synthesizer (Part II)

The TMC 0280 is a single chip speech synthesizer based on the technique of linear predictive coding. The problems of producing high quality synthesized speech at very low cost are discussed and the solutions implemented in the 0280 are presented. The computational core of the unit is a single multiplier, single adder implementation of the two‐multiply lattice filter. All othe required auxiliary functions such as excitation generation, parameter decoding and interpolation, oscillator, interface logic, and 200 mw D/A are also incorporated on this 44 000 mil2 P‐channel MOS bar. Mask programmable options for varying data rate and excitation and filtering characteristics are discussed and features of the companion 131072 bit PMOS ROM are summarized.

Empirical Evidence for a Descriptive Model of Implementation

This article presents a model of factors associated with the successful implementation of a computer-based information system or OR/MS model. The model hypothesizes that two classes of variables, model quality and management support, influence attitudes and perceptions of a model or system. The research model also predicts that attitudes and perceptions, management support, system or model quality, decision style and situational and personal factors are related to successful implementation. In general, the relationships in the model receive support from the data; however, further research is needed, particularly to provide more evidence on possible causal links in the model. Certain classes of variables are also difficult to relate to implementation success, including decision style and personal and situational factors. If the evidence for the model is considered sufficient to take action, implementation strategies should concentrate on several key variables. First, the quality of the model must be high, both in terms of logic and user interface. Favorable attitudes and perceptions should be stressed during development of a model or system. Management support should be encouraged and solicited and the implementor should try to consider different decision styles. Finally, personal and situational factors are likely to be related to success. The purpose of this article is to summarize the findings of nine empirical studies which furnish data to test hypotheses derived from a descriptive model of implementation. It is hoped that hypothesis testing and models of implementation such as those proposed in [14] along with empirical studies will provide a better understanding of the variables associated with successful implementation.

An optically isolated digital interface for the SKED system

A digital interface to support the SKED software system in recent versions of the PDP-8 computer. One printed circuit card of interface logic and optical isolators can be installed in the OMNIBUS to provide 24 input and 36 output lines to external panels containing input simulation switches and input or output indicators.

A user — oriented synchronisation system for a hybrid problem

The purpose of the paper is to present a hybrid software, as well the associated special function of the logical interface, wich accounts for the part of parallel interaction between the analog and digital computers in a hybrid problem.

A multiplexed vectored interface logic system for control of behavioral experiments

An interface was constructed which enabled a minicomputer to control operant conditioning experiments with a minimal amount of software recognition and input/output instructions. The hardware consisted of a real-time clock, logic to input a unique number with each change of state of digital input, and logic and solid state drivers to control standard, commercial 24 V behavioral stimuli.

A pneumatic logic interface for valve throttling

The control advantages of manual throttling valves can be achieved with air−operated valves without any sacrifice to the inherent advantages of pneumatic control. The interface circuit is placed between system controls and the valve, and requires no modifications to existing equipment, other than the rerouting of air lines and power input to the solenoid valve. All systems controls, whether manual or automatic, remain fully functional. The use of this logic interface permits precise valve positioning resulting in pressure and throughout control necessary for sputtering and other applications.

An Automated Electron-Beam Mask Generator

An over-all system approach has been undertaken to make electron-beam microfabrication practical in a production environment at throughput rates which make it economically attractive to semiconductor manufacturers. An electron-beam system designed for fabrication of IC masks at final size in one step is described. Novel features include an ultrahigh-speed 16-bit digital deflection system, high-vacuum compatible x–y table and a field-emission source. System features described are single operator performance, multiple methods to input mask designs, high-speed deflection system, and (intelligent) beam logic interface and CAD system. The system is capable of producing 1.0-μ lines with ± 0.2-μ precision over a 0.25×0.25-in. scan field with coverage of 3×3-in. masks using step and repeat techniques. The system also includes an automated load-lock, cryopumped vacuum system and a high-speed 16-bit minicomputer. System parameters such as throughout time, writing speed, and factors affecting these parameters will be discussed.

Automated Digital Measurements of CV Curves and Derivatives, and of Capacitance Transients for Semiconductor Evaluation

A system of instruments is presented for automated digital measurements of voltage and/or time dependent capacitances. The system has been designed for the evaluation of semiconductor materials and devices. It is based on a fast capacitance-inverse-to-frequency converter (FCFC), where a direct conversion is obtained with high accuracy, and where the device to be tested can be subject to dc, modulated, and pulsed voltage bias. The output frequency (of the order of 1 MHz) accurately foliows capacitance variations, even if occurring in short times (less than 100 Ms). Biasing circuits, a multichannel scaler, and logic interface circuits complete the system. Stationary and nonstationary CV curves and time variations of capacitances can be accuratety measured. The precision can be improved by averagng over many repetitions of the measurement. Derivatives (first and higher orders) of CV curves can also be directly and accurately measured by using a technique based on voltage modulation and synchronous reversible counting. This feature also makes it possible to obtain accurate measurements of doping profiles in semiconductors. Representative experimental results obtained with the system are shown.

A three-parameter magnetic tape data recording system

A three-parameter coincidence data collection system has been constructed based on the use of computer compatible magnetic tape. The system was designed for use at the thermal neutron capture gamma-ray facility at the Georgia Institute of Technology Research Reactor. Up to three 12 bit words can be used to describe the coincidence event. The first two words consist of the output from two analog-to-digital converters (ADC) e.g. two 2048 channel energy spectra. The third word consists of the output of a 256 channel ADC e.g. time spectrum, plus four “status registers”. The system is highly versatile and operates in the one-, two- or three-parameter mode. The interfacing logic is based on the use of commercially available circuit boards. Each function of the logic can be tested via commands from a PDP-8 series computer although the device is completely independent of the computer when operating in the data acquisition mode.

An Astronomical Interface for a Small Computer

Interface logic has been assembled which permits a small computer to record variable star data at high speed, display the accumulating light curve in real time, and exercise control over the data acquisition process. The interface design is quite general and has been used successfully to implement several other instrumental systems.

General-Purpose Equipment for Human Factors Research

The small laboratory that engages in a variety of human factors experiments must rely on equipment that can be easily assembled into widely different configurations. This article discusses analog computing units, digital logic modules, and interface and auxiliary equipment as these may be used in the small human factors or behavioral sciences laboratory. A novel use of a desk-top general-purpose digital computer, modified to allow it to serve as “nerve center” for conducting experiments and processing data, is then described.

Digitization of ultrasonic images.

The authors describe a method for digitizing diagnostic ultrasonic data using a system originally constructed for use with radioisotope scan data. A commercial ultrasonic unit drives the transducer and amplifies the preliminary echo signal. The output signals from the ultrasonic unit are fed to a programmable digital logic interface coupled to a 4,096-word memory. The data can then be transferred directly to a PDP-9 computer for data manipulation or to computer-compatible magnetic tape for permanent storage.

Handeinstellbare programmsteuerung für camac system

This instrument conforms to the CAMAC-System specified in the Publication “EUR 4100e”. It is adapted to computers like PDP8L of DEC. The crates can be controlled directly by the PDP8L, without an additional logic interface (system controller). For simple automatic programs, for adjusting and optimizing experiments without computer the Camac Manual Control has been developed. The outputs of this adjustable hardware-programmer deliver the same electrical signals as the output of the PDP8L, thereby enabling the control of up to 7 crates. The purpose of the Manual Controller is to have the possibility to set a limited number of single instructions by pushbuttons as well as logical niveaus, e.g. inhibit, clear, Initialize, read, write, print etc. The unit also allows an automatic control of the Camac Devices by delivering a number of hardware instructions in automatic cycles. Data set by 6 decade switches are written into the addressed modul register, the contents of registers can be displayed or printed out by a teletype. An array of swithches enables the preselection of the addresses of registers to be printed out.