DOI:10.1049/jiee-1.1939.0150

出版商:IEE    

年代:1939

数据来源: IET

摘要:

This paper describes how it is possible to determine the minimum radius at which a four-aerial Adcock direction-finder may be calibrated for instrumental error without introducing spurious effects due to the proximity of the calibrating transmitter to the direction-finder. It is shown that this minimum radius depends upon the spacing of the aerials, the wavelength, and the inherent accuracy of the direction-finder to be calibrated.In most cases of practical interest, the minimum radius is found to be between 0.6λ and 3.5λ. Such distances, while usually easily attainable on the short wave band, may not be possible in the case of medium or long wavelengths.

DOI:10.1049/jiee-1.1939.0154

出版商:IEE    

年代:1939

数据来源: IET

DOI:10.1049/jiee-1.1939.0155

出版商:IEE    

年代:1939

数据来源: IET

摘要:

The paper: discusses the conditions peculiar to aircraft operation in respect of radio-telegraphy and radio-telephony. Particular stress is given to those conditions not usually met with in other applications of radio-communication and especially to the sources of interference to reception and of danger to the aircraft and its occupants.It concludes with a brief reference to a few special applications of radio in aviation, and while no attempt is made to describe the equipment itself the fundamental principles on which its construction is based are briefly given.

DOI:10.1049/jiee-1.1939.0158

出版商:IEE    

年代:1939

数据来源: IET

摘要:

In the first part of the paper the authors discuss the main valve characteristics which are of importance in instrument design, and describe types of valves specially designed for instrument purposes.The principles are outlined of the various types of valve instruments for the measurement of alternating voltages (including “slide-back,” peak, grid-leak, and anode-bend voltmeters), and of voltmeters and electrometers for direct voltages; and methods of measuring very small values of current and power are described. Reference is also made to other applications such as harmonic analysis, frequency measurement, and the measurement of physical quantities.The paper concludes with a brief comparison between valve-operated and other types of instrument and indicates possible future lines of development.

DOI:10.1049/jiee-1.1939.0160

出版商:IEE    

年代:1939

数据来源: IET

摘要:

Much has been written concerning the fundamental physics of fluctuation phenomena, but the methods to be used in computing signal/noise ratio in the complex circuits of modern communication engineering have never been fully described. This paper gives particulars of two methods by which such computations can be made by the ordinary processes of circuit analysis, no reference to the obscure physical mechanism ofthe effects being necessary.In the first method, voltage representation, the fluctuations associated with valves and resistances are represented by generators injecting voltages of specified mean-square value in series with each valve or resistance. In the second method, current representation, the representation is by a current injected by a hypothetical generator, having infinite internal impedance, connected in parallel with the valve or resistance. Either method may be used, and their relative values in given circumstances are discussed.Both representations appear devoid of physical significance and neither has been rigorously justified theoretically, but extensive experiments have shown that exact calculations of fluctuations in complex networks can be made by their use.

DOI:10.1049/jiee-1.1939.0169

出版商:IEE    

年代:1939

数据来源: IET

DOI:10.1049/jiee-1.1939.0170

出版商:IEE    

年代:1939

数据来源: IET

摘要:

The importance of providing adequate protection against the risk of fire and electric shock due to faults developing on high-voltage discharge-tube circuits has recently come into prominence on account of the extensive use of such apparatus for industrial purposes. The paper explains the peculiar difficulties met with in devising suitable protective devices, and, after describing the principal types of equipment at present available, gives details of-certain recent developments for which the author has been responsible.

DOI:10.1049/jiee-1.1939.0171

出版商:IEE    

年代:1939

数据来源: IET

摘要:

The paper describes a method of harmonic analysis in which the selective properties of the quadrant electrometer are utilized. The major portion of the energy necessary for the operation of the electrometer is derived from an external circuit by means of thermionic valves and it is therefore possible to secure accurate analyses of complex waves of small amplitude, satisfactory results being obtained with a rootmean-square value of 1 volt. In the body of the paper a general description of the apparatus is given and experimental results are cited to show the degree of accuracy that may be expected, while in the Appendices a more detailed investigation is made into certain points concerning the theory of the method.

DOI:10.1049/jiee-1.1939.0172

出版商:IEE    

年代:1939

数据来源: IET

DOI:10.1049/jiee-1.1939.0175

出版商:IEE    

年代:1939

数据来源: IET