DOI:10.1049/ree.1968.0128

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The solar cell battery system, which provides power for the experiments, data handling equipment, tape recorder, telemetry transmitter and command receiver on the Ariel III satellite, is described, with particular reference to novelfeatures and the techniques employed to ensure adequate performance with the utmost reliability.

DOI:10.1049/ree.1968.0131

出版商:IERE    

年代:1968

数据来源: IET

摘要:

Some design aspects of the Ariel HI v.h.f. communications system are described with particular emphasis on the measures taken to enhance reliability. Throughout the design and development of the satellite common-user electronics equipment, component and circuit redundancy techniques have been employed wherever practicable in order to achieve the maximum degree of reliability. These redundancy techniques can be applied to low-frequency circuits without serious degradation of performance; at v.h.f., however, the techniques create intolerable difficulties.The command receiver, transmitter, and other units comprising the v.h.f. system were designed for maximum reliability, using redundancy techniques wherever possible. In addition to these measures, a stand-by transmitter was incorporated. The implications of this major modificationin terms of its improvement to overall reliability, and its effect upon the command system is discussed.As a common aerial system was used for the command receiver, and the telemetry transmitter, sufficient isolation of the transmitter was required to maintain the command receiver sensitivity. A solution adopted for this purpose is mentioned and this is followed by a general description of the command system, telemetry link and constructional techniques. Operational results since launch are included.

DOI:10.1049/ree.1968.0133

出版商:IERE    

年代:1968

数据来源: IET

DOI:10.1049/ree.1968.0135

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The paper describes measurements of amplitude modulation,frequency modulation and total noise spectra for several types of klystrons and backward-wave oscillators. Computations of the noise to be expected have also been carried out and the theoretical and experimental results are compared.

DOI:10.1049/ree.1968.0136

出版商:IERE    

年代:1968

数据来源: IET

摘要:

The most accurate piston attenuators work at frequencies below 100 MHz and standard piston attenuators are usually operated at a fixed frequency such as 30 MHz or 60 MHz. In designing a comparator in which attenuators operating at any frequency up to, say, 3 GHz can be compared with a standard over a wide range of attenuation up to 100 dB, a number of problems had to be solved. Chief among these was the need to keep the noise sufficiently below the signal level at — 107 dBm and the need to design frequency changers which are linearto much better than 0 01 dB over the range of levels — 7 dBm to — 107 dBm. The paper describes how these problems were solved in the design of a comparator which would function with a c.w. source of any frequency between 0.18 GHz and 1 GHz with an uncertainty of comparison well within ±001 dB.

DOI:10.1049/ree.1968.0137

出版商:IERE    

年代:1968

数据来源: IET

DOI:10.1049/ree.1968.0138

出版商:IERE    

年代:1968

数据来源: IET