摘要:

The author describes the work done since 1923 on the Midi and Paris-Orleans Railways, which were amalgamated a few years ago. The paper concludes with an account of the results obtained from electric traction.

DOI:10.1049/jiee-1.1938.0035

出版商:IEE    

年代:1938

数据来源: IET

DOI:10.1049/jiee-1.1938.0038

出版商:IEE    

年代:1938

数据来源: IET

摘要:

This paper presents a somewhat simplified consideration of the processes occurring in the magnetic recording of sound on steel tape, and describes some of the apparatus and methods used in this country in its application to broadcasting.A brief historical account is given of the early uses of magnetic recording. The essential processes involved are then discussed in a simplified form, and the effects of tthe finite longitudinal spread of the recording field, and of the self-demagnetization of the tape, are considered before the question of background noise is introduced.In the next section certain fundamental experiments are described, followed by a brief account of various possible methods of saturating, recording, and reproducing. Considerations relating to the conditions for the optimum working of any particular arrangement are put forward, with the results of tests of two of those which are now in use. Some details are given concerning the tape itself, after which a recording machine is described.The paper concludes with a short account of the technical and programme service requirements for a recording system for use in connection with broadcasting, and a description of a recording channel at the British Broadcasting Corporation's premises at Maida Vale.

DOI:10.1049/jiee-1.1938.0039

出版商:IEE    

年代:1938

数据来源: IET

摘要:

The paper describes an improved recorder for indicating the direction of arrival of transient impulses continuously throughout the day. The polar diagram of the receiver has a width of 20° and is unambiguous. The analysis of three years' records shows that most of the atmospheric disturbance reaching a station in England arrives from the west or south-west, but that during summer afternoons sources to the east and southeast are productive together with storms of a purely local character. The disturbed azimuths appear closely related to the bearing of the great tropical thunderstorm centres, but the intensity of disturbance from each is dependent on the ionization conditions prevailing over the path to the receiver, at the time each region is productive. Curves are given from which the probable intensity of atmospheric in any direction at any time may be roughly determined.

DOI:10.1049/jiee-1.1938.0041

出版商:IEE    

年代:1938

数据来源: IET

摘要:

A review is given of recent developments in magnetic materials, including alloys for permanent magnets, “soft” materials having large initial and maximum permeabilities, and materials with constant permeability over a wide range of magnetizing force. Particular reference is made to dispersion-hardening alloys, the attainment of high degrees of purity in iron and iron alloys, improvements in sheet materials, the properties of nickel-irons, and of complex alloys based on them, after various thermal, magnetic, and mechanical treatments, and the characteristics of powdered materials.

DOI:10.1049/jiee-1.1938.0042

出版商:IEE    

年代:1938

数据来源: IET

DOI:10.1049/jiee-1.1938.0044

出版商:IEE    

年代:1938

数据来源: IET