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Radio and Electronic Engineer

Issue 6 • Date June 1968

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Displaying Results 1 - 11 of 11
  • Broader horizons

    Publication Year: 1968
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    Freely Available from IEEE
  • A wideband circular array for h.f. communications

    Publication Year: 1968 , Page(s): 321 - 328
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (783 KB)  

    This paper describes a study of the use of a single ring array of monopoles for a wideband multiple-beam aerial system for communications.Directional patterns are calculated for 24- and 32-element circular arrays over the frequency band 1-5-10 MHz and for different types of array excitation (or element combination in the case of a receiving array).The calculations are backed by experimental measurements on a model circular array operating over the band 200¿1365 MHz. The study shows that low side-lobe levels (¿6 to ¿9 dB) and acceptably small variations of beam-width, can be achieved over the above frequency band. View full abstract»

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  • Institution Notices

    Publication Year: 1968
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    Freely Available from IEEE
  • Television network switching at the post office tower in london

    Publication Year: 1968 , Page(s): 329 - 341
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1943 KB)  

    Television network switching equipment is concerned principally with setting up vision and sound routes between various sources and destinations. Due to the growth of the network system this equipment has developed from the simplicity of patch-panels to a complexity requiring a certain amount of automation. In the equipment recently installed at the Post Office Tower in London and also in three provincial centres, provision is made for storing two patterns of connections and their switching times. Pre-setting of information is carried out manually but the actual switching operations are under the control of a clock system driven by pulses derived from the speakingclock TIM. Provision is made for overriding the clock or changing the stored information when last-minute schedule changes occur. The equipment is designed for 625-line colour operation. View full abstract»

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  • The iris satellite

    Publication Year: 1968 , Page(s): 342 - 344
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    First Page of the Article
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  • Propagation of uniform plane waves in a Fabry-Perot resonator containing ammonium dihydrogen phosphate (ADP) as dielectric

    Publication Year: 1968 , Page(s): 345 - 351
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (743 KB)  

    The propagation of uniform plane electromagnetic waves in a uniaxial medium has been developed from an electrical rather than an optical viewpoint. Explicit formulae for the ratios of the magnitudes of electric field components along the three co-ordinate axes are worked out for ordinary and extraordinary wave normals, and the direction of energy propagation for both waves is also developed. The results are applied to a Fabry-Perot resonator with a dielectric of ADP and it is shown that the wave normal resonance angle is the same when the incident and reflected wave velocities inside the resonator differ by a maximum as when they are identical. This leads to circular interference fringes as with an isotropic medium which is a desirable feature in a Fabry-Perot intensity modulator. View full abstract»

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  • Letter to the Editor: Using references to retrieve current articles

    Publication Year: 1968 , Page(s): 352 - 353
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  • Instruments, electronics and automation exhibition

    Publication Year: 1968 , Page(s): 354 - 356
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  • Adjustment of the 4-port single-junction circulator

    Publication Year: 1968 , Page(s): 357 - 360
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (397 KB)  

    The 4-port junction circulator differs from the 3-port junction in that the circulation adjustment cannot be reduced to an admittance a t c h i n g procedure. To adjust the 4-port junction circulator requires setting three independent variables. A unique procedure is given for setting the three independent variables one at a time in terms of the scattering coefficients of the junction. The procedure is demonstrated on an experimental waveguide junction. View full abstract»

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  • An invariant alignability factor and its significance

    Publication Year: 1968 , Page(s): 361 - 368
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    The sensitivities of the port immittance to small immittance and large reactive changes of the self-immittance at the opposite port of a linear active two-port network are investigated. A new 'invariant alignability factor', S, is defined as the inverse of the maximum modulus of the sensitivity. 6 is an invariant for interchange of the ports, arbitrary lossless terminations and immittance substitution. It precisely expresses the maximum interaction between the two ports and is related to earlier stability and performance factors, S can be evaluated by a simple experimental method. The power gain margin of any active linear two-port network is 8 nepers, when 8 is very small compared with unity. The upper limit of its maximum power gain for a given performance factor is inversely proportional to the square of 8. View full abstract»

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  • Generation of random digital numbers with specified probability distributions

    Publication Year: 1968 , Page(s): 369 - 375
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    Current interest in digital simulation models has given rise to the need to produce random digital numbers. Several methods of generating pseudo-random sequences of digital numbers are discussed. These methods are used as a basis for generating truly random digital numbers whose probability of occurrence can be set by programming a simple patch-board. View full abstract»

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