DOI:10.1049/ree.1966.0084

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The overall design philosophy of an industrial telemetry and telecontrol system is approached in a general manner, and its leading characteristics are deduced. The constituent parts of such a system are then examined in some detail. Particular attention is paid to the practical communication aspects of the system, and to the logic circuits which could be employed in its construction. The enunciated principles are illustrated by reference to a particular commercial equipment.

DOI:10.1049/ree.1966.0085

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The working principle of a simple binary circuit employing one tunnel diode is explained qualitatively using the trajectory of the operating point during its to and fro motion between the two stable states of equilibrium by the application of rectangular current pulses of either polarity. Trajectories in either case were constructed by the graphical method using the principle of Ussui.

DOI:10.1049/ree.1966.0086

出版商:IERE    

年代:1966

数据来源: IET

摘要:

A brief description of the Instrument Landing System is followed by a detailed survey of its specific vulnerabilities to various forms of interference and the conclusion is drawn that, if I.L.S. is to be used as the guidance component of an automatic landing system for all-weather operations, an effective monitoring system must be provided.

DOI:10.1049/ree.1966.0087

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The paper reports an investigation of the general problem of radio propagation influences on the performance of the azimuth channel of the conventional Instrument Landing System. The main text is an attempt to define the characteristics of I.L.S. signals that are more directly relevant to monitor design. To support the theoretical studies a localizer was installed at a disused airfield and the azimuthal guidance course was comprehensively monitored by means of signal probes erected in the required flight path. Geometricaloptical and diffraction theories were employed to assess the effects of possible re-radiating objects. The validity of the theoretical methods employed was checked by measurements at the disused airfield and at London Airport (Heathrow). The difficult task of assessing the probability of harmful interference between localizers operating in temperate climates on the same nominal frequency has been attempted by analysing the published data and augmenting it by recording anomalously propagated signals. Many flight trials have been undertaken in order to investigate the effect of overflying aircraft on the performance of the azimuth channel. Experimental records have been analysed in amplitude and frequency and compared with theoretical predictions. Results obtained with a ‘stationary’ landing aircraft have been used since the case of a real landing aircraft is at least no more critical in terms of the protection required, and an assessment has been made of the volume of air space which must be kept clear in order that there shall be a very low probability of interference from overflying aircraft.

DOI:10.1049/ree.1966.0088

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The phase of a received very-low-frequency signal, recorded as a function of time, has been utilized to investigate (a) the frequency off-set between two remotely located atomic frequency standards and (6) the variations of the diurnal phase shift— which is a characteristic of the phase comparison records.A comparison of the precision obtained in the measurement of the frequency off-set by using 20 and 60 kHz transmissions over a path length of 1800 km, reveals that the measurement is more precise on 20 kHz transmissions. The diurnal phase shift, studied from the standpoint of the two-mode model, shows that the second mode interference increases with increasing frequency in the range 16-20 kHz as can be seen from the curves theoretically computed for diurnal phase shift as a function of path distance. Experimental results are presented for comparison.Variations of the general phase pattern and the monthly variation of the diurnal phase shift are also presented. The diurnal phase shift is found to be a minimum during the period of solstice and a maximum during equinox. The general consistency of the phase shift is shown to depend both on path length and its orientation. The value of the change in effective height of ionospheric reflection calculated from the yearly mean diurnal phase shift for a long propagation path is found to be in good agreement with the value used in theoretical calculations.

DOI:10.1049/ree.1966.0089

出版商:IERE    

年代:1966

数据来源: IET

摘要:

When a large number of triggered spark-gap switches are used in parallel, as in many thermonuclear fusion experiments, it is essential to detect when one fires late. A further requirement is that any spark-gap which breaks down spontaneously will be indicated, even if other gaps fire in consequence. Both functions are performed by the 40-channel equipment described, lamp indication being used for early and late firing, with a time bracket adjustable from 10 to 50 ns. The system used is insensitive to interference and poor wave-shape.

DOI:10.1049/ree.1966.0090

出版商:IERE    

年代:1966

数据来源: IET