DOI:10.1049/ree.1966.0076

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The limitations of existing pivoted arms are outlined, followed by brief details of some past and present radial tracking arms. The advantages of very low tip mass cartridges tracking at <0.2 g, and the design requirements of suitable arms, are discussed as an introduction to the principles and design of a radial tracking arm with a side thrust of <3 dynes at 33½ rev/min (‘Trutrack’), in which the weight of the arm, head and counterweight is supported by a float immersed in silicone fluid.Details of setting-up techniques and methods used to seal and package the liquid filled trough to withstand transport shocks of 100 g are given.The calculation and measurement of inertial forces resulting from eccentric and warped records, wow, frequency and damping of various vibrational modes of the arm are described. Details of the magnetic repulsion bearing system used in the device, with some performance curves, are given, and the problems of designing reliable low drag liquid signal contacts discussed. Materials and techniques used to ensure long term reliability of the device are described.

DOI:10.1049/ree.1966.0077

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The paper surveys the current state of knowledge of the properties of the ionosphere, in particular those which have become more important or more accurately known through the use of sounding rockets and artificial Earth satellites. The atmosphere and its electrical propertiesare first discussed. An account of wave-electron interaction and incoherent scattering from electrons is followed by consideration of the roperties of the D, E and F regions, and finally scatter propagation is briefly discussed.

DOI:10.1049/ree.1966.0078

出版商:IERE    

年代:1966

数据来源: IET

摘要:

Numerical solutions have been obtained for unit step response of m-derived delay lines in which inductive coupling exists between adjacent sections. It is shown that for optimum coupling both rise-time and overshoot are improved in comparison to constant-Ar delay lines.

DOI:10.1049/ree.1966.0079

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The high level of feedback in transistor r.f. amplifiers is well known, and neutralizing must normally be regarded as merely reducing (not eliminating) this feedback. Criteria are established for gain and stability, and also for distortion of the frequency-response curve. Fromthe latter criterion, very simple practical design rules are arrived at: these are applicable to both single and multistage amplifiers, at any frequency. The results are summarized in a graph, which gives 'maximum seful gain' and design data on the preferred (fixed neutralized) designsystem: corresponding data for a non-neutralized system are also shown.

DOI:10.1049/ree.1966.0081

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The tapered waveguide is regarded as a two-mode system, the modes being the forward and reverse waves. A reflection parameter can be defined, relating the amplitude of the reverse wave generated at a point in the taper to the amplitude of the forward wave at that point. The reflection parameter can be regarded as a coupling parameter between the two modes, and coupled-mode theory can be used to obtain theoverall reflection coefficient of the taper. It is shown how to estimate the error in this result. The error may become large if the frequency approaches the cut-off frequency of a guide whose cross-section is the same as that of the narrow end of the taper. The estimation of the error can be used to show how close to cut-off the theory is valid. A detailed analysis is given for the case of a homogeneously-filled tapered waveguide, with perfectly conducting walls, working in the dominant mode. The design of reflectionless tapers is discussed in the light of the results obtained.

DOI:10.1049/ree.1966.0082

出版商:IERE    

年代:1966

数据来源: IET

摘要:

A description is given of a graphical derivation of the switching trajectories of a transistor-tunnel diode circuit. With this method quicker solutions are achieved than when an analytical approach is used and the resultant accuracy compares favourably with that of solutions obtained using an analogue computer.

DOI:10.1049/ree.1966.0083

出版商:IERE    

年代:1966

数据来源: IET