摘要:

The PAL system and its relationship to the N.T.S.C. system is described. The effects of phase distortion and sideband limitation separately and in combination are analysed. The attributes of various decoding arrangements are compared and the action of the delay line discussed. The possibility of error correction prior to transmission is outlined and finally the consequences following the use of systems with a line sequential component are described.

DOI:10.1049/ree.1967.0023

出版商:IERE    

年代:1967

数据来源: IET

摘要:

Cryotron storage cells are attractive for random access memory because of their broad tolerances. In the past, their lower size limit has been set by the fact that their read-out signal becomes too small and short to be sensed by conventional amplifiers. A new sensing method has been developed which removes this limitation, so that the lower limit of cell size is now determined by fabrication technology only.This paper describes this technique as well as a number of old and new cryotron cells compatible with it. Cell dimensions are calculated in terms of fabrication parameters and a comparison of the densities of various bit and word organized designs is made.

DOI:10.1049/ree.1967.0024

出版商:IERE    

年代:1967

数据来源: IET

摘要:

A flying-spot film scanner was developed, capable of a short sweep in any direction from any of the 1024 × 1024 precise positions on the face of a 5-inch c.r.t. The spot is imaged on a film with 1 : 1 optics.Fine black lines on the film can be located with an accuracy of about 3 μm. The width and degree of blackness of these are also recorded and these data are transferred to a computer on its demand.The computer processes the data and provides fresh instructions for the scanner so that the following sweep vector can be optimally specified.

DOI:10.1049/ree.1967.0025

出版商:IERE    

年代:1967

数据来源: IET

摘要:

One of the techniques used in the optimization of controlled plant is that of hill-climbing. This technique is most usefully employed on-line and, therefore, must operate with the normal random operating signals. The performance (as opposed to economic) criterion of the plant's operation is usually chosen to be the mean square error. This paper investigates the variations in the shape of the curves of mean square error against the forward, and rate feedback, gains of a generalized system as the bandwidth and sharpness of cut-off of the random signals are varied. Considering the signals as filtered white noise, it is shown that optimization becomes difficult if the filter pole is of order greater than three, and the filter pole must be positioned carefully relative to the system's open-loop poles, if optimization is to be achieved at all using both parameters.

DOI:10.1049/ree.1967.0026

出版商:IERE    

年代:1967

数据来源: IET

摘要:

RC interstage coupling filters can be used in a cascaded transistor amplifier to produce a gain of 77 dB at a mid-frequency of 60 MHz with 20 MHz bandwidth. A logarithmic amplifier can be arranged by using active band-pass filters of unity gain in conjunction with the RC coupled stages.

DOI:10.1049/ree.1967.0027

出版商:IERE    

年代:1967

数据来源: IET

摘要:

A normalized low-pass prototype filter, terminated in equal value resistances, is considered and the insertion loss is given, as a function of normalized frequency and value of the terminating resistance. The root-locus of the poles of the insertion-loss function is plotted showing the effect of variation of the value of the termination and comparison is made with the pole locations of Butterworth and Chebyshev filters of the third order. The treatment is extended to two identical prototype filters in cascade and in this case the root-locus of the poles of the insertion-loss function is compared with the poles of fifth order Butterworth and Chebyshev filter functions. Insertion-loss curves are given for various terminations for both single and cascaded filters.

DOI:10.1049/ree.1967.0028

出版商:IERE    

年代:1967

数据来源: IET

摘要:

A magnetic thin-film store of 1024 words, each of 50 bits, has been developed which repetitively read-rewrites at 2 MHz. The 2 MHz store has operated for 5000 hours without change. A similar store of 128 words cycles at 3 MHz.From the basic method of film operation, the element dimensions, flux linkage and signal outputs have been derived and measured. A brief description of the method of construction precedes some conclusions on the suitability of the design for commercial production.

DOI:10.1049/ree.1967.0031

出版商:IERE    

年代:1967

数据来源: IET

摘要:

This paper discusses the use of transfer matrices in the synthesis of cascaded electronic networks. Previous work on this subject has been performed by trial and error methods, but here it is shown that for certain special classes of transfer matrix, the solution, if indeed a solution exists, can be predetermined logically.

DOI:10.1049/ree.1967.0032

出版商:IERE    

年代:1967

数据来源: IET