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Radio and Electronic Engineer

Issue 11.12 • Date November/December 1984

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Displaying Results 1 - 9 of 9
  • Stanley Richard Burbidge

    Publication Year: 1984
    Save to Project icon | PDF file iconPDF (173 KB)  
    Freely Available from IEEE
  • John Robert Miller

    Publication Year: 1984
    Save to Project icon | PDF file iconPDF (173 KB)  
    Freely Available from IEEE
  • Integrated optics

    Publication Year: 1984
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (434 KB)  

    First Page of the Article
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  • A laser flashover test method for cathode-ray tube displays

    Publication Year: 1984 , Page(s): 439 - 444
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (762 KB)  

    Large-scale integration parts are easily damaged by the transient currents that result from e.h.t. flashover in a cathode-ray tube. It is therefore necessary during design to provide adequate circuit protection and, further, to ensure by testing that the protection is sufficient to remove the likelihood that flashover-induced failures will happen during normal operation. The purpose of this work was to evolve a test method that could achieve universal acceptance, so that it could be applied to both monochrome and colour units containing hard- or soft-flash c.r.t.s. The method chosen uses Q-switched laser pulses to initiate flashover discharges to the focus electrode and then employs the focus-to-final-anode gap as a surrogate spark gap to transfer flashover energy to the remaining c.r.t. connections. The measurements taken during manufacturing plant life-testing have been used to confirm the number of discharges required in a test to verify design. View full abstract»

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  • Transmission of broadcast services over a 140 Mbit/s digital bearer: a joint BBC/BT pilot scheme

    Publication Year: 1984 , Page(s): 445 - 456
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1762 KB)  

    This paper describes a joint BBC/BT pilot scheme involving the transmission of broadcast quality sound and vision signals and other services over a 140 Mbit/s digital bearer between London and Birmingham. Terminal equipment, designed and constructed by the BBC, is described which assembles one PAL television signal, including teletext and associated stereo signal, with 12¿5 Mbit/s available for further high quality audio channels, telephony, data and error correction. The means of transmission involves the use of an optical fibre system, a radio relay channel and a coaxial line system. Initial evaluative studies are briefly outlined. View full abstract»

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  • Applications of closed-loop stepping motor control in multi-motor systems

    Publication Year: 1984 , Page(s): 457 - 461
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (802 KB)  

    Stepping motors, as digital machines, are commonly used in electromechanical systems since they can easily be interfaced to and controlled by computers. Electrical and mechanical interaction in multiple-motor systems, however, can lead to severe control problems, and in intelligent systems such as programmable XYtables, rotor position feedback from each machine is necessary to implement effective control algorithms. This paper describes new methods of detecting rotor position in stepping motors with chopper drives. By monitoring the motor phase current waveforms and detecting the chopping current rise-times, motor phase excitation angle may be varied continuously over a step cycle, and performance may be maximized. Two industrial applications are described: accurate trajectory control in an XY table, where close position coordination between two motors is necessary; and velocity control in a two-motor system where mechanical interaction creates a variable inertia load for one motor. View full abstract»

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  • An evaluation test for speech synthesizers

    Publication Year: 1984 , Page(s): 462 - 466
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    Commercially available speech synthesizers are now being used extensively in talking machines. As their numbers continue to grow, it is essential to establish standard evaluation tests as quality control checks in their manufacture. A contribution towards this goal is described in this paper. Listeners heard the output of two commercial synthesizers. By identifying the basic units of speech (phonemes) which are wrongly perceived and comparing these with known confusions arising in listening to real speech under difficult conditions, it was possible to identify the limitations of a given synthesizer. View full abstract»

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  • Microprocessor control of two-phase a.c. induction motors

    Publication Year: 1984 , Page(s): 467 - 472
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (816 KB)  

    In spite of their inherent mechanical advantages, the use of two-phase a.c. induction motors in control applications has faded during the last ten years in favour of d.c. motors. This is due mainly to their lower efficiency and difficulty in control, particularly when using d.c. supplies. This paper describes a new approach to the control problem based on the use of `six-step¿ d.c.-a.c. inverter drives in which complementary pairs of power v.m.o.s. f.e.t.s are used to implement the inverters interfaced via timer chips to the controlling microcomputer. View full abstract»

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  • Hybrid networks and their uses in radio-frequency circuits

    Publication Year: 1984 , Page(s): 473 - 489
    Cited by:  Papers (7)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1936 KB)  

    The general properties of hybrid networks are described and two main types, the quadrature and the 0¿180° types, are identified. A list of uses of hybrid networks in radio frequency circuits follows. Seventeen configurations of hybrid networks are given with diagrams showing the variations of their input and output parameters with frequency. The 3 dB transmission line coupler is described in more detail and multiplexers are mentioned. View full abstract»

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