DOI:10.1049/ree.1969.0067

出版商:IERE    

年代:1969

数据来源: IET

摘要:

The paper reviews the present trends in the use of computers for process control through the combined experiences of the activities of the authors' organizations in the field. Examples quoted showing the wide range of application which has to be covered include integrated production control, hierarchical control and direct digital control. Conclusions are drawn about the effect which the requirements will have on the design of suitable equipment in the next few years.

DOI:10.1049/ree.1969.0068

出版商:IERE    

年代:1969

数据来源: IET

摘要:

The system is designed to record pulse-shape information of singly occurring pulses with rise-times down to 1 ns. The basic theory of the ‘interrogate pulse’ sampling scheme is described and a system to implement this scheme is outlined. The proposed system employs short term analogue storage of the sampled input, followed by a fast multiplexed analogue to digital converter and digital storage. Some results from an experimental instrument using this system are given.

DOI:10.1049/ree.1969.0069

出版商:IERE    

年代:1969

数据来源: IET

摘要:

The characteristics of typical 1/fnoise spectra which have been observed, and the physical models proposed for their explanation, are reviewed. In m.o.s. transistors the 1/fspectrum extends over at least ten decades, and the effect of the gate field on the frequency index has been investigated. It is argued that these measurements support the theory that the conductivity of the inversion layer fluctuates due to electrons tunnelling to and from traps in the silicon oxide dielectric. It is shown that the tunnelling model satisfies Halford's statistical criterion.

DOI:10.1049/ree.1969.0070

出版商:IERE    

年代:1969

数据来源: IET

摘要:

The problem of the precise control of the temperature of liquid flowing through a tank containing a heater is one which is important and familiar in the process-control industry. When the heater is electrical the thyristor is a natural choice for the main controller. A simple and novel method of triggering the thyristors is described in which the power dissipated in the heater is a linear function of the control signal. The method is compared with the conventional non-linear and linearized arrangements and its electronic implementation is described. A 0.75 kW model has been designed to demonstrate the principle. With the same basic circuitry but with more powerful gating circuits the arrangement could be used to control very large powers

DOI:10.1049/ree.1969.0071

出版商:IERE    

年代:1969

数据来源: IET

摘要:

A pencil-and-paper method of designing multi-level logic circuits is presented. The approach is intuitive rather than systematic. It bears the same relation to the design of circuits with gates of limited fan-in (as is the case with most microcircuit families) as does the Karnaugh-map method to two-level circuits and gates with unlimited fan-in, NAND/NOR systems are considered, and a graphical procedure, based on Karnaughmaps, is followed.

DOI:10.1049/ree.1969.0072

出版商:IERE    

年代:1969

数据来源: IET

摘要:

A logarithmic diode is defined as one showing a forward characteristicIα exp (eV/mkT) where the factormis independent of voltage (though not necessarily of temperature) over at least four decades of current. Many commercial diodes show such a characteristic withmin the region of 1.5. It is shown that this behaviour cannot be explained by the theory of Sah, Noyce and Shockley and a modified theory is proposed, based on the assumption that the diode current is predominantly due to Shockley-Read-Hall traps non-uniformly distributed in the depletion layer. The theory is shown to be consistent with observed currentvoltage-temperature characteristics of a number of specimens.

DOI:10.1049/ree.1969.0073

出版商:IERE    

年代:1969

数据来源: IET

摘要:

Higher-order active networks using the Horowitz decomposition and only one active element (amplifier, negative impedance converter) are considered. Such networks are particularly sensitive to the changes of theactive element and can eventually start oscillations. The stability of these networks is studied and it is shown that a special design can virtually eliminate the danger of oscillations for functions up to the sixth degree. A unique criterion is given for tests of the functions and for the stability margin.

DOI:10.1049/ree.1969.0074

出版商:IERE    

年代:1969

数据来源: IET

摘要:

This algorithm evaluates, in binary form, log2Nfor a given value ofN> 0 using steps which are easily reproduced by logic blocks. It is also possible to extend this to obtain 2x, the antilogarithm to base 2 of a given num berx.

DOI:10.1049/ree.1969.0075

出版商:IERE    

年代:1969

数据来源: IET

摘要:

By using a network transformation the frequency dependence of the balancing and matching properties of a transmission-line balun can be evaluated by studying rational network functions.

DOI:10.1049/ree.1969.0076

出版商:IERE    

年代:1969

数据来源: IET