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Radio and Electronic Engineer

Issue 3 • Date September 1968

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Displaying Results 1 - 11 of 11
  • On being understood

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    Freely Available from IEEE
  • Institution Notices

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    Freely Available from IEEE
  • Synthesis of active filters with optimum sensitivity

    Page(s): 135 - 147
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1393 KB)  

    Two general RC-active-network synthesis procedures previously described by the author are applied to the synthesis of filters. A third synthesis procedure is now described in which Guillemin's parallelladder procedure is used to realize the passive part of the network. This and the previous two procedures use the Horowitz decomposition which optimizes the sensitivity. Amethod for reducing the number of passive elements is explained. The three procedures are used to realize all the possible second-order filter transfer functions. Design tables are included in which the element values are given in terms of the transfer function coefficients. Finally alow-pass, fifth-order, elliptic filter is designed using the tables. View full abstract»

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  • Of Current Interest . . .

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    Freely Available from IEEE
  • Operational aspects of v.h.f. communication and radar surveillance by port operations centres

    Page(s): 149 - 152
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (435 KB)  

    The Port Operations Centre passes information from the shore-based radar station to the ship through the Pilot of the ship by v.h.f. communication. The advantages of such rapid, clear and direct communication between a ship underway within a port and a shore authority are described. The operation of this system and present and future developments are also discussed. View full abstract»

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  • Microwave-link characteristics for a harbour surveillance system

    Page(s): 153 - 160
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    The paper outlines the technical requirements for a broadband, two-way single hop microwave link with hot stand-by facilities and automatic changeover. The basic design of the various units is described. The method of multiplexing the various signals, namely, radar video, radar sync, aerial bearing, two-state controls and supervisory data, is given in outline and also the techniques employed in order to provide continuous 24-hour operation by means of hot stand-by facilities with automatic changeover and sub-unit duplication are described. View full abstract»

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  • A display centre for harbour surveillance and control

    Page(s): 161 - 169
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1597 KB)  

    The operational requirements of a harbour control centre are dominated by the problems of radar surveillance. Narrow channels require a large-scale presentation, which leads to multiple displays, and the difficulties which arise in tracking a target from one display to another. The photographic projector display presents numerous advantages in this respect, as well as in preserving a permanent record. Consideration is given to the design requirements of the different units of the system arising specifically in this application, and the procedure by which a system is designed to suit a particular site, and then integrated with the non-radar equipment which is equally necessary for efficient control of traffic in the harbour and its surroundings. View full abstract»

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  • Computers and Information Processing

    Page(s): 173 - 174
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  • Some aspects of electrostatic transducers

    Page(s): 175 - 180
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    Usually an electrostatic transducer is represented theoretically as an ideal electromechanical transformer followed by a piston-like diaphragm. This is not exact if a thin diaphragm is used. It is shown that by mathematical treatment of known physical relations the four-pole equations (or matrixes) for the relations between acoustical values and electrical ones may be derived. Further it is shown that it is useful to introduce the term of acoustical impedance of the thin diaphragm as a whole which may be represented by an analogue network, having damped poles and zeros at frequencies of the respective modes. A new analogue network of the complete transducer is then given. Curves are shown of normalized impedances of thin diaphragms as a function of relative frequency for different parameters calculated by a computer. View full abstract»

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  • A contribution to the theory of multivibrators employing distributed circuits

    Page(s): 181 - 191
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    The equations relating to the theory of multivibrators employing uniformly distributed circuits as cross-coupling elements are examined. By using integral transform methods, analytic solutions for each state of the multivibrator cycle are obtained. The solutions are expressed in terms of orthogonal functions and are readily adapted to numerical analysis. Advantages of the method over methods based on finite difference techniques are emphasized particularly when stored base charge effects are studied. Numerous results for both symmetric and asymmetric multivibrator configurations are presented. View full abstract»

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