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Proceedings of the IRE

Issue 8 • Date Aug. 1949

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Displaying Results 1 - 25 of 29
  • Table of contents

    Publication Year: 1949 , Page(s): 849
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  • William L. Everitt, Board of Directors, 1949-1951

    Publication Year: 1949 , Page(s): 850
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  • The Valuable By-Product

    Publication Year: 1949 , Page(s): 851
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  • Path-Length Microwave Lenses

    Publication Year: 1949 , Page(s): 852 - 855
    Cited by:  Papers (8)
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    Lens antennas for microwave applications are described which produce a focusing effect by physically increasing the path lengths, compared to free space, of radio waves passing through the lens. This is accomplished by means of baffle plates which extend parallel to the magnetic vector, and which are either tilted or bent into serpentine shape so as to force the waves to travel the longer-inclined or serpentine path. The three-dimensional contour of the plate array is shaped to correspond to a convex lens. The advantages over previous metallic lenses are: broader band performance, greater simplicity, and less severe tolerances. View full abstract»

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  • Mercury Delay Line Memory Using a Pulse Rate of Several Megacycles

    Publication Year: 1949 , Page(s): 855 - 861
    Cited by:  Papers (6)
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    A mercury delay line memory system for electronic computers, capable of operating at pulse repetition rates of several megacycles per second, has been developed. The high repetition rate results in a saving in space and a reduction in access time. Numerous improvements in techniques have made the high repetition rate possible. The use of the pulse envelope system of representing data has effectively doubled the possible pulse rate; the use of crystal gating circuits has made possible the control of signals at high pulse rates; and a multichannel memory using a single pool of mercury has simplified the mechanical construction, reduced the size, and made temperature control much easier. The memory system described makes possible a significant increase in the over-all speed of an electronic computer. View full abstract»

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  • Correction

    Publication Year: 1949 , Page(s): 861
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  • An Analysis of Magnetic Amplifiers with Feedback

    Publication Year: 1949 , Page(s): 862 - 866
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    Two ways of obtaining feedback in magnetic amplifiers are studied. One, termed external feedback, employs a bridge rectifier and separate feedback coils, while the other, termed self feedback, uses two rectifiers so disposed that separate feedback windings are unnecessary. Commutation of the rectifiers, apparently not considered heretotore, is shown to be of major importance. The calculated currents are confirmed satisfactorily, both in shape and magnitude, by experimental checks. The two feedback methods are compared, and it is found that self feedback is advantageous. View full abstract»

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  • Electrical Network Analyzers for the Solution of Electromagnetic Field Problems

    Publication Year: 1949 , Page(s): 866 - 872
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    This is the second part of a paper on the design, construction, testing, and operation of electrical networks capable of obtaining solutions of the wave equation in both two-dimensional, axially symmetric, cylindrical co-ordinates and rectangular co-ordinates. The circuit yields information on TEM, TMom(n) and TEom(n) modes of concentric lines, waveguides, and resonators. Field plots of electric- and magnetic-field configurations are directly available, and resonant frequencies of cavities, equivalent impedance, reactance characteristics, Q, and proragation characteristics can be determined. View full abstract»

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  • Design of Optimum Transient Response Amplifiers

    Publication Year: 1949 , Page(s): 873 - 879
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1368 KB)  

    This paper describes a method based entirely upon transient considerations for the design of amplifiers with optimum transient response in the "least squared" sense. This method is applicable to video amplifiers, symmetrical band-pass amplifiers, and dissymmetrical band-pass amplifiers used with low-level modulation, and has provisions for taking into account noise acceptance and adjacent channel rejection. Examples are given of the results obtained with this method. View full abstract»

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  • Admittance of the 1B25 Microwave Switching Tube

    Publication Year: 1949 , Page(s): 879 - 881
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    The operation of an RCA-1B25 neon-argon-filled glow tube as a switching element in a transmission-line network at ultra-high frequencies has been investigated. A test method has been developed and theory formulated for evaluating the behavior of the tube in terms of an equivalent susceptance and conductance. Experimental measurements have been made which show the variation of the admittance characteristics as a function of gas pressure and of the direct current. View full abstract»

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  • Bridged Reactance-Resistance Networks

    Publication Year: 1949 , Page(s): 882 - 887
    Cited by:  Papers (2)
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    Consideration is given to the various possible six-arm, six-element RC bridged networks of which the parallel-tee is the previously known example. It is found that six symmetrical RC structures exist having the infinite attenuation property of the parallel-tee and other properties differing from those of this structure. The duality of certain pairs of such structures is demonstrated. View full abstract»

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  • Ionospheric Virtual Height Measurements at 100 Kilocycles

    Publication Year: 1949 , Page(s): 887 - 894
    Cited by:  Papers (2)
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    A simple high-power ionosphere sounding equipment for use at low frequencies is described. Its application to the measurement of virtual height at vertical incidence at a carrier frequency of 100 kc is reported. Results of nearly a year of intermittent night-time measurements showed a remarkably large variation in virtual height which ranged from about 84 km to as high as 106 km. Some evidence was found to indicate that frequently at night the reflecting region consists of clouds or patches of ionization, rather than the more nearly uniform ionization characteristic of the regular layers at high frequencies. A rotation of the polarization of the reflected signal with respect to that of the transmitted signal was observed. View full abstract»

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  • The Demodulation of a Frequency-Modulated Carrier and Random Noise by a Discriminator

    Publication Year: 1949 , Page(s): 895
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  • Discussion on "Application of Velocity-Modulation Tubes for Reception at U.H.F. and S.H.F." (M. J. O. Strutt and A. Van Der Ziel)

    Publication Year: 1949 , Page(s): 896 - 900
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  • Contributors to the Proceedings of the I.R.E.

    Publication Year: 1949 , Page(s): 900 - 902
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  • Institute news and radio notes

    Publication Year: 1949 , Page(s): 903 - 907
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  • Books

    Publication Year: 1949 , Page(s): 907 - 909
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  • IRE People

    Publication Year: 1949 , Page(s): 909 - 911
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  • Cover Sheet for Technical Memoranda-A Technique in Information Exchange

    Publication Year: 1949 , Page(s): 912 - 913
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    An account is given of the origin and use of a routine for disseminating new technical information and ideas rapidly and flexibly through the large engineering and research organization of Bell Telephone Laboratories. The essential philosophy back of this routine is that technical memoranda have the status only of the individual engineer's personal authority, and hence may be circulated directly and widely across departmental lines for information and discussion. Departmental policy in relation to such memoranda is established by covering letters where such action is necessary. The objectives approached and benefits accruing from this procedure are briefly discussed. View full abstract»

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  • Radioactive Standards and Methods of Testing Instruments Used in the Measurement of Radioactivity

    Publication Year: 1949 , Page(s): 913 - 922
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    A summnary of the program for standardization of radioisotopes at the National Bureau of Standards is given in this paper, with some of the reasons for need of absolute measurements of radioisotopes in particular uses. This is accompanied by an outline of some of the methods used to ascertain characteristics of commercial instruments used in the measurement of radioactivity, with particular emphasis on those methods used at the National Bureau of Standads for this purpose. View full abstract»

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  • The Columbia Long-Playing Microgroove Recording System

    Publication Year: 1949 , Page(s): 923 - 927
    Cited by:  Papers (1)
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    The Columbia LP (long-playing) microgroove recording system was developed to fill the need for music reproduction which would avoid interruptions not intended by the composer, and which would be of excellent quality at a reasonable cost. This allimportant factor of cost and the public's familiarity with the handling of phonograph records made it desirable to solve the task on the basis of records, rather than tape or wire. Standard 78-rpm records were originally designed to generate sound mechanically by direct transfer of energy from the groove of the record to the vibrating diaphragm. Because the entire acoustical energy had to be extracted from the grooves, these had to be quite rugged, and remained so up until now. The new Columbia recording system was an inevitable outcome of the use of electrical amplification between the groove and the loudspeaker. Today, practically no mechanical energy needs to be extracted from the groove, and thus, for the first time, it has been possible to develop much finer grooves, permitting longer playing time and distortion-free reproduction. View full abstract»

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  • Direct Voltage Performance Test for Capacitor Paper

    Publication Year: 1949 , Page(s): 927 - 931
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    Performance of capacitors on accelerated life test may vary over a wide range depending upon the capacitor paper used. Indeed, at present a life test appears to be the only practical means for evaluating capacitor paper, since, within the limits observed in commercial material, the chemical and physical tests usually made do not correlate with life. Lack of correlation is ascribed to obscure physical factors which have not yet been identified. Generally, several weeks are required to evaluate a paper by life tests of the usual severity. Unfortunately, the duration of these tests is too long for quality control of paper. The desire for a life test which requires no more than a day or two for evaluation led to the development of a rapid dc test. The philosophy of rapid life testing is based upon the experimental evidence that the process of deterioration under selected temperature and voltage conditions is principally of a chemical nature, and also upon the well-known fact that rates of chemical reaction increase exponentially with temperature. Life tests on two-layer capacitors conducted at 130°C provide an acceleration in deterioration many fold more than that obtained in the lower-temperature life tests, and correlate well with these tests. View full abstract»

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  • Some Aspects of Cathode-Follower Design at Radio Frequencies

    Publication Year: 1949 , Page(s): 932 - 937
    Cited by:  Papers (4)
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    Pertinent high-frequency design data including the circuit gain, the gain phase angle, the input impedance in resistive and reactive components, and the maximum allowable input signal voltage may be determined quickly from simple design charts derived by approximations which are applicable over a wide range of frequency and circuit parameters. The only circuit quantities required for use of the charts are the magnitude and phase angle of the cathode load impedance, the internal tube capacitances, and the grid-to-plate transconductance of the tube at the operating point. A discussion of the effects of the grid-to-cathode capacitance on circuit operation at high frequencies is presented, including a critical analysis of the source impedance. It is shown that the source impedance may be greatly affected by the impedance of the grid driving source unless remedial measures are taken. Various circuit changes which reduce or eliminate the undesirable effects of the grid-to-cathode capacitance are offered with discussion and analyses. View full abstract»

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  • Noise from Current-Carrying Resistors 20 to 500 Kc

    Publication Year: 1949 , Page(s): 938 - 942
    Cited by:  Papers (2)
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    Measurements have been made of the effect, first studied by Bernamont that when a direct current is flowing through certain types of resistors, the noise voltage generated at their terminals is considerably in excess of the thermal value. The effect has been investigated for solid carbon-composition, "metallized," palladium film, and "cracked-carbon" resistors, for resistance values from 1,000 to 30,000 Ω, currents from 1 to 10 milliamperes, and at frequencies between 20 and 500 kc. For some individual resistors, especially of the solid carbon-composition type, the noise voltage measured at any frequency in the range stated (with direct current flowing) showed much larger fluctuations than those characteristic of thermal noise, with a detecting system having a response up to a few cps. The fluctuations frequently reached peak amplitudes of several times the mean level of the noise. Several records of the fluctuations; taken on a recording meter, are shown. The fluctuations were particularly large when the current was first applied to any resistor, while its resistance changed to a stable value at a higher temperature, suggesting an analogy to the Barkhausen effect in the magnetization of ferromagnetics. No simple correlation of the occurrence of the fluctuations with other factors has been found. View full abstract»

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  • An Analysis of the Sensing Method of Automatic Frequency Control for Microwave Oscillators

    Publication Year: 1949 , Page(s): 943 - 951
    Cited by:  Papers (2)
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    An analysis is made of the type of automatic-frequency-control circuit that uses a simple cavity resonator for the stable element and either frequency modulation of the controlled oscillator or modulation of the cavity resonance frequency to obtain effective discriminator curves which give a null output for a frequency equal to the average cavity resonance frequency. An analysis is made of the complete automatic-frequency-control loop gain, including the transmission through the cavity as a function of the various parameters and the frequency-modulation swing. A discussion is presented of the best method of decreasing the pulling of the oscillator frequency by the cavity, and the pulling of the cavity frequency by a load which has a variable susceptance. View full abstract»

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Aims & Scope

This Periodical ceased production in 1962. The current retitled publication is Proceedings of the IEEE.

Full Aims & Scope