DOI:10.1049/ree.1971.0059

出版商:IERE    

年代:1971

数据来源: IET

摘要:

The present and future position of p.c.m. microwave line-of-sight systems is reviewed in relation to the more conventional f.d.m.-f.m. microwave systems. A comparison is made of the relative noise performance, transmitter power and system bandwidth between the two systems. The effect of rainfall attenuation is discussed.

DOI:10.1049/ree.1971.0060

出版商:IERE    

年代:1971

数据来源: IET

摘要:

Describes a video noise measuring equipment which has been developed to meet the needs of a television broadcasting organization. The various measuring techniques available for this purpose are reviewed and the chosen method, which employs a sampling technique, is fully described. Details are then given of the practical design together with some remarks on its use.

DOI:10.1049/ree.1971.0061

出版商:IERE    

年代:1971

数据来源: IET

摘要:

An ultrasonic flaw detection equipment has been developed for testing steel tubes at speeds compatible with modern rates of production. The system uses a series of identical probes arranged in a ring encircling the tube. Fast sequential pulsing of the probes, together with slow rotation of the tubes gives effective circumferential scanning speeds several times faster than is obtainable by purely mechanical methods. The probe rings are immersed in a small tank of water through which the tube is passed via specially designed water retaining valves.

DOI:10.1049/ree.1971.0062

出版商:IERE    

年代:1971

数据来源: IET

摘要:

An economical seven-segment display system is described which employs 21 diodes and 7 driving transistors as against 49 diodes and 14 driving transistors in a conventional display. The single driving transistor employed for each segment has to be biased so that it is normally saturated and the lamp is illuminated. To extinguish the lamp, the transistor is held below cut off by providing a suitable excitation.

DOI:10.1049/ree.1971.0063

出版商:IERE    

年代:1971

数据来源: IET

摘要:

A review is made of current electronic instrumentation in use in submersibles, habitats and by divers. The design constraints of the underwater environment and their effect on electronics is discussed. A prediction is made of future requirements in the three applications considered.

DOI:10.1049/ree.1971.0064

出版商:IERE    

年代:1971

数据来源: IET

摘要:

The design considerations and use of a new grey-scale reflectance chart for colour cameras are discussed in relation to some of the parameters of a colour television system. The construction of a prototype chart based on the new design specification is described.

DOI:10.1049/ree.1971.0065

出版商:IERE    

年代:1971

数据来源: IET