Coaxial transmission line filters in which the shunt reactive elements are conducting rods inserted between the inner and outer conductors of the series coaxial transmission line may be analyzed by the use of well-kno...
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Coaxial transmission line filters in which the shunt reactive elements are conducting rods inserted between the inner and outer conductors of the series coaxial transmission line may be analyzed by the use of well-known transmission line equations if only the TEM mode propagates. When other "spurious" modes are important, the problem is not so simple. Some equations are presented for the cutoff frequencies of such spurious modes, and supporting experimental data is included.
The paper treats of the true wave phenomena which take place on a transmission line when switches are opened and closed or when a circuit breaker operates. These phenomena are practically the same in alternating- and ...
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The paper treats of the true wave phenomena which take place on a transmission line when switches are opened and closed or when a circuit breaker operates. These phenomena are practically the same in alternating- and direct-current systems for transmission lines up to say 150 or 200 mi. (240 or 320 km.) in length, and therefore the surges which are described in the paper are the surges which take place when a steady voltage is connected to the line or when the line is disconnected with a steady current flowing in it. The details of line surging which takes place under such conditions are most easily described in terms of what may be called the “ribbon wave„, and the first part of the paper is devoted to a discussion of the ribbon wave. Then a number of practical examples are described in detail. Copyright, 1914 by the AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS
A type of wave filter employing a concentric transmission line is described. Filters of this type are especially applicable to ultra-high-frequency operation where their physical size becomes reasonable and where the ...
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A type of wave filter employing a concentric transmission line is described. Filters of this type are especially applicable to ultra-high-frequency operation where their physical size becomes reasonable and where the conventional lumped-constant filters become practically unrealizable. It is shown that the addition of a simple lumped-reactance element will result in a sharp cutoff characteristic analogous to that exhibited by a conventional m-derived lumped-constant filter but over a limited frequency band. This latter filter has allowed simultaneous transmission and reception using the same antenna, in the 30- to 42-megacycle band, transmitter pouer 150 watts, receiver sensitivity 5 microvolts, with a frequency difference of only 0.9 megacycle. It is shown that a 14 per cent increase in driving-point impedance of the filter can be obtained if the filter line is shortened 0.065 wavelength and tuned to resonance with a shunt capacitance. This result is applicable directly to the use of transmission lines as tank circuits when very high driving point impedance is required.
Theory and applications of coupled nonuniform transmission lines are described. Matrix representations of a general coupled nonuniform transmission line are presented, by means of which the behavior of any coupled non...
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Theory and applications of coupled nonuniform transmission lines are described. Matrix representations of a general coupled nonuniform transmission line are presented, by means of which the behavior of any coupled nonuniform transmission line maybe completely described. Among a wide variety of applications of coupled nonuniform transmission lines, two typical networks, one the coupled nonuniform transmission-line folded all-pass network and the other the coupled nonuniform transmission-line directional coupler, are treated in detail. Equivalent circuit representatious of these two networks are presented, which enable the designer to synthesize them in a greatly simplified manner by making use of the theories now available for more conventional single nonuniform transmission lines. In addition, the properties of these two networks using coupled exponential line are investigated. Design procedure is also given for asymmetrical coupled exponential-line directional couplers having excellent characteristics.
This paper presents a practical design for unbalanced insulation of transmission lines and describes lightning performances on 70- and 140-kV lines. The basic practice of unbalanced insulation is to install one circui...
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This paper presents a practical design for unbalanced insulation of transmission lines and describes lightning performances on 70- and 140-kV lines. The basic practice of unbalanced insulation is to install one circuit at a higher insulation level than another circuit in order to eliminate double-circuit flashover. The effectiveness of this design was demonstrated by laboratory tests and field experiences. Double-circuit flashover should be considerably decreased when the unbalanced insulation line is properly designed.
Multistage microwave transistor amplifiers of simple construction have been developed. In these amplifiers, unit amplifiers of the same design are connected in cascade with short transmission lines inserted between ea...
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Multistage microwave transistor amplifiers of simple construction have been developed. In these amplifiers, unit amplifiers of the same design are connected in cascade with short transmission lines inserted between each amplifier. The n-stage (three-, four-, five-, six-, and seven-stage) amplifiers designed for the 4-GHz band gave power gains n times that of the unit amplifier (4 dB) and flat bandwidths of about 1000 MHz. The stripline circuit of the amplifier is fabricated on alumina substrates in the usual way. The amplifier has the disadvantage of poor input and output impedance matching. However, this problem was solved by integrating isolators in the input and output ports of the multistage amplifier. Noise performance of the amplifier is also described.
Methods for transmission and distribution system reliability analysis currently being developed and used require that the expected values of component outage rates and outage durations be known. The paper describes ho...
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Methods for transmission and distribution system reliability analysis currently being developed and used require that the expected values of component outage rates and outage durations be known. The paper describes how the required component parameters can be estimated from field data. Also described are methods of placing confidence limits on the parameters estimated. The methods presented were developed through a study of six years of field records provided by a utility company. Sample expected outage rates and outage durations for various components such as transmission lines, substation transformers, and circuit breakers are presented. Also presented are data which tend to confirm the distributional assumptions made in system reliability analysis methods.
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