摘要:

To eliminate some of the skilled human effort in arranging the layout of the components of a microcircuit on a substrate, it is proposed that the process should be aided by a digital computer. A fully automated system does not seem possible at present. The method which has been suggested, and partially developed relies on the automatic production of a rough layout which is unconstrained in size. This is then rearranged by human intervention, to a suitable electrical and geometrical form, the designer communicating with the machine using a simple drawing language and viewing the progress of the work using an on-line graphical display. The process does not permit changes in topography and this still remains a major problem.

DOI:10.1049/ree.1968.0038

出版商:IERE    

年代:1968

数据来源: IET

摘要:

A vacuum-deposited thin film metal-insulator-metal (Al-SiO-Au) device, after an electro-forming process, emits hot electrons,and constitutes a cold cathode. An array of 25 of these Al-SiO-Au cold cathodes, each of approximately 0.1 cm2area, is used with a phosphor screen in an alpha-numeric display panel, which is clearly visible under normal laboratory lighting conditions. The normal cathode bias is about 12 V. The normal screen potential is about 3 kV. Screen brightness varies directly with the screen potential and exponentially with cathode bias. Pulse operation shows th t the rise and decay times of the light output are limited only by the phosphor used. The thickness and composition of the cathode insulator film determine the operating characteristics, notably life. Cathodes of high emission current density, for example, 250 µA cm−2, may operate for about 1 hour. Some with initial high ratio of emission current to current circulating through the cathode, for example, up to one per cent, may operate for 1000 hours. Cathodes of emission current density that is approximately uniform over the cathode area, and therefore suitable for a display, operate for several hundred hours. Failure mechanisms are due to continued forming during operation,and dielectric breakdown.

DOI:10.1049/ree.1968.0039

出版商:IERE    

年代:1968

数据来源: IET

摘要:

An analysis is given of frequency multiplication with the ideal step-recovery diode in the series-mode of operation. Only one conduction angle per period of the fundamental frequency is allowed. The series resistance of the diode is assumed to be different from zero. General and explicit formulae are given for the input impedance, the output power and the power efficiency. The validity of the approximations is discussed throughout. It is shown that the efficiency, -q, of the power conversion is proportional to 1/n2, and that the maximum value for 17 is about 15% for a times 10 multiplier in this series-mode of operation.

DOI:10.1049/ree.1968.0040

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The technique used for a frequency modulation measurement depends upon various factors such as the value of modulation index and frequency deviation. Even with the same set of variables more than onemethod of measurement may be available and the choice of method is decided as much by its ease of application as by its inherent accuracy.Some of the more commonly used methods of frequency modulation measurement are discussed and the conditions under which each is used are examined. The errors aris ing in the use of these methods and the precautions which must be taken to minimize these errors are also examined. Finally, a commercial type of f.m. meter is described. This instrument depends for standardization on one of the basic methods but covers a wide range of application with good accuracy.

DOI:10.1049/ree.1968.0041

出版商:IERE    

年代:1968

数据来源: IET

摘要:

Karnaugh maps are used as a graphical technique for minimizinglogical functions. They are usually employed where there are up to four literals, or with some difficulty for a maximum of six literals. It is proposed that the use of these maps can be extended to eight literals by arranging that each cell of the map be divided to form a subsidiary Karnaugh map.

DOI:10.1049/ree.1968.0042

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The principle of operation of a novel free-running transistor multivibrator is presented. The circuit is based on the application of a complementary switch, the operation of which is controlled by a single timing network. This circuit provides a suitable means of generating rectangular pulses having rise- and fall-times in the nanosecond range.The circuit exhibits some other useful features which include excellent thermal stability and considerable loading capabilities for both resistive and capacitive loads, and less dependence on power supply variations.The experimental model which was built to verify the design operated properly in the frequency range extending from very low frequencies t frequencies over 5 MHz when only the timing capacitor was changed.

DOI:10.1049/ree.1968.0043

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The characteristics of band-limited random noise are employed to measure the signal transmission properties of non-coherent pulse radar receiving systems used for evaluating back-scatter signals from the ground,sea and precipitation clutter targets. a scheme using a calibrated microwave noise generator source and amplitude distribution and spectrum analysing equipment is employed, as both clutter and noise signals can be characterized by their amplitude distributions and spectra. theoretical and measured results for a radar receiving system fitted with a logarithmic amplifier are compared and the effect of distortions explained

DOI:10.1049/ree.1968.0044

出版商:IERE    

年代:1968

数据来源: IET