By Topic

Electrical Engineers - Part IIIA: Radiocommunication, Journal of the Institution of

Issue 13 • Date March-April 1947

Filter Results

Displaying Results 1 - 21 of 21
  • Electro-acoustic transducers and intercommunication systems for aircraft

    Publication Year: 1947, Page(s):441 - 451
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1649 KB)

    The paper is a review of audio-frequency communication instruments and techniques used in military aircraft during the war years. It indicates also the purpose and trend of further developments in this field. A brief exposition is first given of the mechanism of speech communication in and from noisy locations, and of the requirements. thereby imposed on the design of transducers and audio circuit... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Recent developments of aircraft communication aerials

    Publication Year: 1947, Page(s):452 - 458
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1333 KB)

    The paper describes the progress made in recent years in aircraft aerial design. The impedance characteristics of several typical kinds of aerial are stated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A panoramic receiver (3.5-20 Mc/s)

    Publication Year: 1947, Page(s):459 - 460
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (261 KB)

    The receiver is designed to indicate the presence, frequency and relative magnitude of strong signals in the frequency band 3.5¿¿20 Mc/s, displaying all such signals simultaneously in ¿¿panoramic¿¿ form on a 12-in cathode-ray tube. To cover this large frequency range in the one instrument, a superheterodyne arrangement with the intermediate frequency higher than the signal frequencies is employed.... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reference-crystal-controlled v.h.f. equipment

    Publication Year: 1947, Page(s):461 - 474
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2233 KB)

    A brief allusion is made to the value and usage of v.h.f. equipment capable of crystal-controlled operation on a large number of channels, any one of which may be selected by the setting of one or more dials to the cipher or letter combination characterizing this channel. A survey is made of the methods of obtaining this facility from a small number of crystals built into the apparatus, one of whi... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Power supplies for aircraft communication equipment

    Publication Year: 1947, Page(s):475 - 483
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1296 KB)

    The paper presents a brief historical review of the development of power supplies for aircraft communication equipment. A study is made of the aircraft general electrical system in so far as it affects radio power supply, particular attention being paid to the system voltage and the means employed for its regulation. A brief mention is made of the only experimental a.c. system which has yet been a... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radio interference from aircraft electrical equipment

    Publication Year: 1947, Page(s):484 - 492
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1310 KB)

    This paper deals with the radio-frequency disturbances caused by the normal operation of electrical equipment in aircraft. A brief account is given of the events leading to the adoption of the present system of suppression, reference is made to the special problems encountered, and attention is drawn to the more common sources and means of propagation of interference. Methods of reducing interfere... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on "Military and aeronautical communication" at the Radiocommunication Convention, 26th March, 1947

    Publication Year: 1947, Page(s):492 - 495
    IEEE is not the copyright holder of this material | PDF file iconPDF (774 KB)
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The authors' replies to the discussion on "Military and aeronautical communication"

    Publication Year: 1947, Page(s):495 - 496
    IEEE is not the copyright holder of this material | PDF file iconPDF (392 KB)
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A method of obtaining linear frequency deviation in a wide-band frequency-modulation system

    Publication Year: 1947, Page(s):497 - 502
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (601 KB)

    This report describes a method of obtaining linear frequency deviation in a wide-band frequency-modulation system. The primary cause of harmonic distortion in a frequency-modulation system is the non-linearity of the slope of the reactance valve. A method is described of linearizing this slope, and thereby obtaining very good linearity of the frequency modulation. The harmonic distortion is of the... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pulse communication on lines

    Publication Year: 1947, Page(s):503 - 510
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (797 KB)

    A dispersive medium, i.e. one in which the waveform of an individual pulse changes its type at successive points during propagation, is not normally appropriate for pulse communication, since greater efficiency can be achieved through it in other ways. However, conditions can arise in which it becomes desirable to employ such a link, and it is necessary to discover the restrictions imposed by the ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new method of wide-band modulation of pulses

    Publication Year: 1947, Page(s):511 - 516
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (632 KB)

    In a pulse-modulation system it may be required to convey a wide band of modulation-frequency components with a high degree of fidelity, as when the modulating signal consists of a multichannel carrier wave having its intelligence channels separated on a frequency basis. In this case the occurrence in the pulse system of any appreciable non-linear distortion introducing intermodulation amongst the... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The development of the Wireless Set No. 10: an early application of pulse-length modulation

    Publication Year: 1947, Page(s):517 - 527
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1680 KB)

    The experimental development of the system is described briefly, being a historical record of the design of an interlaced pulse-length modulated, multi-channel telephone circuit, and its application to a centimetre-wave radio link. The multiplexing equipment, radio sender and receiver, and the complete station, are described. A more detailed account of the electrical and mechanical difficulties en... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A common-wave duplex pulse-communication system

    Publication Year: 1947, Page(s):528 - 532
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (697 KB)

    The paper details the principles of a duplex pulse-communication system using only one carrier frequency and suited for air-to-air and air-to-ground radiotelephony. The duplex facility is achieved by suppression of the receivers at each end of a communication link. Pulsephase modulation is employed and the pulse-recurrence frequencies of the transmissions in the two directions are unsynchronized. ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noise problems in pulse communication

    Publication Year: 1947, Page(s):533 - 545
    Cited by:  Papers (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1650 KB)

    Formulae for random noise in the audio-frequency output in pulse-communication receivers are given for pulse-length-, pulse-phase- and pulse-frequency-modulation systems in which the received pulses are sliced; they are also given for pulse-amplitude modulation. Noise resulting from random distribution of the i.f. phase at the onset of pulses is also considered. Optimum slicing level giving minimu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-power pulse communication at centimetre wavelengths

    Publication Year: 1947, Page(s):546 - 550
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (553 KB)

    The paper describes several applications of microwave radar technique to pulse telephony for a single channel. Two methods of modulation were used, one of which has the advantage of reducing interference by a gating system with automatic synchronization. Pulsed magnetrons and klystrons were used, giving an output peak power of ¿ kW and higher. Some measurements were made of the signal/noise ratio... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Random noise characteristics of a pulse-length-modulated system of communication

    Publication Year: 1947, Page(s):551 - 555
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (645 KB)

    The paper deals with a theoretical analysis of the random noise characteristics of a pulse-length-modulated system of communication. The result is demonstrated by two different methods, one of which is rigorous and based on the frequency spectrum of a rectangular pulse, while the other is an approximation based upon calculation of the average value of the pulse waveform, plus noise, integrated ove... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The spectrum of modulated pulses

    Publication Year: 1947, Page(s):556 - 564
    Cited by:  Papers (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1119 KB)

    Some methods proposed for evaluating the spectra of modulated pulse trains are discussed. The basic pulse-frequency, -phase, -length and -amplitude modulation systems are defined and the spectrum of a train of rectangular pulses sinusoidally modulated in any one of these ways is derived. Modulation by more than one tone is also considered. It is shown that in none of these methods is there any har... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Some theoretical and practical considerations of pulse modulation

    Publication Year: 1947, Page(s):565 - 572
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1055 KB)

    This paper gives a summary of theoretical and practical studies on the properties of pulse-phase modulation, developed mainly in 1943. The properties of pulse-phase modulation are studied by means of Fourier transformations. Although some approximations are introduced, the calculations lead to the following definite conclusions: (1) Pulse-phase modulation introduces no amplitude distortion except ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A 60-cm multi-channel system employing pulse-phase modulation

    Publication Year: 1947, Page(s):573 - 583
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1693 KB)

    A description is given of the principles of operation of a pulse-modulated radio-telephone system intended for ground point-to-point use and providing up to twelve simultaneous channels of two-way telephone communication. Each channel is capable of accommodating up to four channels of teleprinter signals as an alternative to speech. The operating frequency band is from 450 to 500 Mc/s, and directi... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discussion on "Pulse communication" at the Radiocommunication Convention, 26th March, 1947

    Publication Year: 1947, Page(s):583 - 587
    IEEE is not the copyright holder of this material | PDF file iconPDF (782 KB)
    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The authors' reply to the discussion on "Pulse communication"

    Publication Year: 1947, Page(s):587 - 588
    IEEE is not the copyright holder of this material | PDF file iconPDF (244 KB)
    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The Journal of the Institution of Electrical Engineers - Part IIIA: Radiocommunication was published by the IET in 1947.

Full Aims & Scope