Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887

Radio and Electronic Engineer

Volume 26, Issue 3, September 1963

Volumes & issues:

Volume 26, Issue 3

September 1963

International co-operation in space research
A high power audio frequency push-pull transistor amplifier to drive an electro-magnetic vibrator
  • Author(s): R.F.C. Bennett
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 191 –196
  • DOI:  10.1049/ree.1963.0119
  • Type: Article
  • + Show details - Hide details
  • p. 191 –196 (6)
    A 1 kVA electro-magnetic vibrator, having a nominal impedance of 10 ohms and requiring a 150 V peak excitation source, is taken as a model for studying the problems involved in driving large vibrators.The output transformer, usually associated with audio power amplifiers, determines the amplifier low frequency response. A design for a high power transformerless transistor push-pull amplifier is considered, with emphasis in particular on the problems associated with transistor series/parallel arrangements, and the power handling requirements of an amplifier driving a load of low power factor.
    Add to favourites
    Export citations
Hybrid digital/analogue servomechanisms
  • Author(s): G.B. Kent
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 197 –201
  • DOI:  10.1049/ree.1963.0120
  • Type: Article
  • + Show details - Hide details
  • p. 197 –201 (5)
    The paper is an introduction to hybrid digital/analogue servo systems utilizing the application of digital techniques to conventional closed-loop servo systems. The term hybrid is used to describe systems where the error signal is derived digitally and then converted into an analogue signal for the operation of the power source. This results in an improved system accuracy compared with that obtainable using conventional analogue methods, and avoids many of the difficulties associated with the pure digital approach.An introduction consisting of a comparison of the salient features of analogue and hybrid servo systems provides a background against which the underlying principles and design features of both velocity and position servo systems are discussed. The constituent elements of each system are derived in block diagram form with parallel references to their analogue counterparts. The paper concludes with an assessment of the advantages of hybrid servomechanisms and a brief review of the various fields of application of such systems.
    Add to favourites
    Export citations
Discussion on “Hybrid digital/analogue servomechanisms”
The N.I.R.N.S. 7 GeV proton synchrotron
A high-resolution electronic sector-scanning sonar
  • Author(s): V.G. Welsby  and  J.R. Dunn
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 205 –208
  • DOI:  10.1049/ree.1963.0123
  • Type: Article
  • + Show details - Hide details
  • p. 205 –208 (4)
    The success of sea-trials of an experimental pulsed sonar system using ‘within-pulse’ electronic scanning has led to the development of a new version using a considerably larger number of channels and a shorter wavelength in the water. The new system, which has 30 channels and works at a carrier frequency of 500 kc/s in the water, is designed for a maximum range of 100 yards and a scanned sector of ± 15 deg. Pulse lengths down to 100 μs can be used, corresponding to a range resolution of about 6 in. Facilities are provided to permit a rapid change-over from normal additive signal processing to a multiplicative process which is capable of approximately doubling the angular resolution of the system, at the expense of some reduction in effective maximum range. Initial trials have confirmed that the performance of the equipment meets the design specification.
    Add to favourites
    Export citations
Points from the discussion on “A high-resolution electronic sector-scanning sonar”
Square-loop ferrites with sinusoidal magnetization
  • Author(s): J. Wood
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 209 –212
  • DOI:  10.1049/ree.1963.0125
  • Type: Article
  • + Show details - Hide details
  • p. 209 –212 (4)
    The switching speed of square-loop ferrite cores is limited mainly by the restricted speed of domain wall movement, and not by eddy currents as in a metallic core. Their use in magnetic amplifiers and modulators allows the excitation frequency to be raised, giving greater bandwidth. This paper uses a simple theory of flux reversal in square-loop ferrites to predict switching speed with sinusoidal magnetizing force, and gives the results of experiments carried out to test this theory.
    Add to favourites
    Export citations
A telecommunication and telecontrol system for a crude oil pipeline
Direct wide-band phase shifters
  • Author(s): P.V. Indiresan
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 227 –229
  • DOI:  10.1049/ree.1963.0127
  • Type: Article
  • + Show details - Hide details
  • p. 227 –229 (3)
    Two functions which differ only in phase and that by 90 deg, are related to each other by the Hilbert transform and to derive one from the other it is necessary to know the values of the input function at all times, past as well as future, right up to infinity. However, the amplitude error will be less than ± 1 dB if the input values are considered up to a time duration equal to the period of the lowest frequency component in the signal. It has been explained that speech waves vary comparatively slowly and hence, their future form can be taken to be the same as that at the present instant. A direct wide-band phase shifting circuit which utilizes these ideas to give an arbitrarily small error in phase and an amplitude response constant to within ± 1 dB, over a 14 : 1 range of frequencies, is described.
    Add to favourites
    Export citations
New speaking clock using magnetic recording
A multi-function unit static switching system for industry
  • Author(s): C.G. Cargill
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 231 –240
  • DOI:  10.1049/ree.1963.0129
  • Type: Article
  • + Show details - Hide details
  • p. 231 –240 (10)
    The most important requirements of a control engineer for a static switching system are that it should be easily understood and easily applied. The features considered necessary to meet these requirements are discussed. A range of units having these features has been produced and the principal unit is described in detail. Some indication of its versatility is given and other units of the system are described briefly. The problems involved in extending static switching to the simple industrial application are discussed and the special facilities introduced to overcome them are explained. Two examples of the use of multi-function static switching in industry are given. Some of the factors to be considered when assessing the cost and value of static switching are outlined and future extensions to the range of units are mentioned.
    Add to favourites
    Export citations
Discussion on “A multi-function unit static switching system for industry”
Television standards conversion
Adaptation of sonar techniques for exploring the sediments and crust of the Earth beneath the ocean
  • Author(s): J.B. Hersey ; S.T. Knott ; D.D. Caulfield ; H.E. Edgerton ; E.E. Hays
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 245 –249
  • DOI:  10.1049/ree.1963.0132
  • Type: Article
  • + Show details - Hide details
  • p. 245 –249 (5)
    The ‘continuous seismic profiler’ is an instrument system for studying the structure of sediments and rock beneath the sea floor by the seismic reflection method. Pulses of sound reflected at near-normal incidence are automatically timed and correlated by the recording method used in echo sounding. The sound source is chosen to give a repeatable pulse having a broad spectrum rich in low frequencies. One sound source called the ‘sparker’ has been developed into a unit with a power supply delivering 25,000 joules. A second source called the ‘boomer’ generates a sound pulse by means of the repulsive force induced between a flat spiral coil and a contiguous plate of aluminium when a large pulse of current passes through the coil. The latest ‘boomer’ is designed to accept 13,000 joules of electrical energy. Recordings of good quality can be made in 3000 fathoms of water from a ship proceeding at 6 knots and echoes have been recorded well over one second after the initial bottom reflection.These sound sources and recording techniques have also been applied to studying layered structures in the sediments by the refraction method and by studying reflection of sound from these layers as a function of angle of incidence.
    Add to favourites
    Export citations
Points from the discussion on “Adaptation of sonar techniques for exploring the sediments and crust of the Earth beneath the ocean”
Signal processing in radar and sonar directional systems (with special reference to systems common to radar, sonar, radioastronomy and ultrasonics)
Activation analysis applied to steel production
Obituary
The condenser microphone and some of its uses in laboratory investigations
  • Author(s): P.V. Brüel  and  W.J. Parker
  • Source: Radio and Electronic Engineer, Volume 26, Issue 3, p. 261 –274
  • DOI:  10.1049/ree.1963.0137
  • Type: Article
  • + Show details - Hide details
  • p. 261 –274 (14)
    The development of techniques for measuring sound pressures are discussed, with special reference to the accuracy of various methods. After comparing the advantages and disadvantages of different kinds of laboratory microphone in use today, the characteristics of the condenser microphone are discussed more fully. The theory brings to light the factors which govern the frequency response, sensitivity, acoustic impedance, and other important qualities. Then, following some comments on the principles of designing miniature microphones, methods of calibration are discussed.Taking the loudspeaker as an example of electro-acoustic equipment which is to be investigated, most of the possible acoustic test arrangements are considered, partly with a view to deciding which, if any, give the best objective criterion of fidelity. Other uses of the condenser microphone are also discussed briefly.
    Add to favourites
    Export citations
Radio engineering overseas …

Most viewed content for this Journal

Article
content/journals/ree
Journal
5
Loading

Most cited content for this Journal

We currently have no most cited data available for this content.

Print this page
This is a required field
Please enter a valid email address