DOI:10.1049/ree.1965.0001

出版商:IERE    

年代:1965

数据来源: IET

摘要:

The design and construction of a complete system for the accurate determination of the earth's magnetic field in a rocket vehicle are described. The flight equipment utilizes the principle of proton-free precession to produce a frequency analogue of the intensity of the geomagnetic field; this frequency is independent of the attitude of the rocket. Some special features of the instrument which are necessary to make it perform satisfactorily in the severe environmental conditions of a rocket flight are discussed in detail. During play-back of the telemetered and recorded precession signals the ground equipment described improves the quality of the data and converts them to a form more suitable for analysis and interpretation.The results of the first instrument-proving flight are presented and briefly discussed

DOI:10.1049/ree.1965.0002

出版商:IERE    

年代:1965

数据来源: IET

摘要:

The output of an antenna that scans an incoherent source distribution is ‘smoothed’, that is, it contains fewer rapid variations with angle than the true source distribution. This is because the antenna rejects or reduces high spatial frequency components of the source spectrum. Source spectrum components passed by the antenna can be restored to their correct value by data-processing but such techniques usually yield a non-physical approximation to the source distribution. In a new technique that enhances angular resolution, the best mean square match to the restored source data is determined, and the minimum amount of extrapolated data added to guarantee a physical approximation to the sources surveyed by the antenna

DOI:10.1049/ree.1965.0004

出版商:IERE    

年代:1965

数据来源: IET

摘要:

While the literature is quite complete on transistor parameters below the avalanche region and a considerable amount of work has been directed to the region where complete breakdown occurs, the intermediate region has received very little study. This paper deals with the behaviour of the transistor in the border region of avalanche and particularly treats transistors of very high cut-off frequency. This is done in terms of the general four-terminal network parameters. The effects of avalanche on the a cut-off frequency and the maximum frequency of oscillation are discussed by using the admittance parameters and the short circuit current gain,which were measured experimentally. Further, it is shown that operation under avalanche conditions can extend the maximum useful operating frequency

DOI:10.1049/ree.1965.0006

出版商:IERE    

年代:1965

数据来源: IET

摘要:

Seismic signals from a single event usually contain a number of components (phases) which have travelled by different propagation paths, or with a different mode of propagation. These may be superimposed and obscure signal components of interest. Seismic background noise may also be of sufficient amplitude to obscure the signal onset, which is often of relatively small amplitude, or even obscure the whole signal.An array of seismometers, spaced over a distance comparable to the signal wavelength, can be used as a filter to separate and help identify signal components on the basis of azimuth and apparent velocity at the Earth's surface. A signal/noise ratio improvement is also obtained for the first arrival, improving the accuracy of locating the hypocentres using triangulation methods from several stations.Linear cross arrays have been operated during recent years by the United Kingdom Atomic Energy Authority and many events analysed, an example of which is shown. The theoretical performances of symmetrical cross and L-shaped arrays are given in the form of directivity patterns, and their method of use described. Correlation methods are shown to be necessary for obtaining a good azimuth or velocity response, and their advantages and limitations considered

DOI:10.1049/ree.1965.0007

出版商:IERE    

年代:1965

数据来源: IET

摘要:

Several non-linear antenna systems are investigated in detail and their responses compared. The response of these antennas is computed for two targets with the following parameter variations: (1) target angular separation varying from zero to one null-to-null beamwidth; (2) target correlation varying between zero and unity; (3) target relative phase varying between zeroand 360 deg. The resulting data are presented in the form of resolution curves and pointing errors, where the pointing error is given by the angular deviation of the peaks of the antenna response from the actual target locations. The results indicate that non-linear processing improves resolution, defined as the ability to separate two closely-spaced targets, for all levels of correlation between the target returns. The amount of improvement beyond that of a linear arrayvaries somewhat with the particular array configuration and, in general, depends on the sacrifice in gain, or signal/noise ratio.The theoretical studies were accompanied by an experimental program which both confirmed the theoretical results and demonstrated the practical feasibility of non-linear processing antennas for radar applications.

DOI:10.1049/ree.1965.0011

出版商:IERE    

年代:1965

数据来源: IET