Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics

Kron's method of network analysis is based on the assumption of invariance of power between the primitive and actual networks. It is shown by an example and also theoretically that this assumption needs some explanation. The necessary transformation formulas are proved by an application of Kirchhoff's laws to the networks and lead to an equation more general than Kron's; the voltage and current tr... View full abstract»

A Laplace transform method shows the solution of the second-order differential equation with time-varying coefficients and an arbitrary forcing function. However, the method is not restricted to second-order equations. View full abstract»

One of the more troublesome characteristics of a transistor is its rather pronounced sensitivity to temperature.1,2 Consequently, in the design of a transistor circuit it is necessary to provide diligently for changes in device parameters resulting from both self-heating effects and ambient variations. Of primary importance is the stabilization of the d-c operating point.3,4 In addition, it is oft... View full abstract»

Characteristics of a system of two capacitively coupled tuned anode oscillators and possible modes of oscillation are analyzed. With certain adjustments of circuit parameters, asynchronous simultaneous oscillations are possible, while with other adjustments, single-frequency oscillations are obtained at one time. Possible use of the system as a frequency storage device is suggested. View full abstract»

A simplification of Hayashi's method of symmetrical components for the steady-state analysis of periodically interrupted circuits is presented. The mathematical basis of the method is shown in terms of eigenvalues and eigenvectors of a transfer matrix. The method is illustrated by derivation of the equations for a balanced 3-phase bridge-type inverter and by the solution of the equations for the s... View full abstract»

Expressions relating a-c permeability and core loss to the dynamic hysteresis loop geometry are derived. It is shown that for inductions of 5 kilogauss or less, the a-c permeability associated with an iron-core inductor represented by a resistance in parallel with an inductance is equal to the slope of the major axis of the dynamic hysteresis loop. If the iron-core inductor is represented by a res... View full abstract»

Hamilton's Modified Principle (HMP) is used to solve two nonlinear problems. The amplitude, frequency, and stability in the limit cycle of a simple pentode oscillator are calculated in order to demonstrate the principle. A standard graphical method finds the amplitude of oscillations, and results are compared with experimental data. For the case under consideration, the HMP solution gives better a... View full abstract»

Transient voltages continue to cause insulation failures of transformers in a variety of applications. There is evidence that some voltage transients may include frequency components up to 100 mc (megacycles) of substantial peak-to-peak amplitude. Conventional techniques for securing reasonably accurate oscillographic recordings of high-frequency transients were found to be inadequate. Systems wer... View full abstract»

A high-voltage capacitance ratio bridge based on the current comparator principle is described. The inherent advantages of this bridge are high sensitivity and high accuracy without the necessity of a secondary balance. By suitable design the bridge is made direct reading in capacitance ratio and dissipation factor. It has a resolution of 1 ppm (part per million) and an accuracy of approximately 1... View full abstract»

A method is presented for the measurement of the variation of capacitance with voltage in gas-dielectric capacitors. It consists of applying to the capacitor a direct voltage and using a small alternating voltage to measure the capacitance variation. The direct voltage coefficient obtained in this manner differs from that obtained with alternating voltage, and this relationship is studied theoreti... View full abstract»

A description is given of a very-small-impulse voltage divider which is insulated by compressed gas. The divider was designed for the measurement of steep-front impulse waves, and its errors have been evaluated by the step-response method, using a pressurized sphere gap. It was then used for measuring the volt-time curve of a sphere gap, and the results have been compared with those obtained by ot... View full abstract»

A method for measuring total core loss by means of a modified Hay bridge is established. It is shown from Kirchhoff's laws that the new method is applicable when the time rate of change of flux in the core is nonsinusoidal and exhibits quarter-wave symmetry. An experimental comparison of the modified Hay bridge method and the reflecting wattmeter indicates agreement within about 2% when the wavefo... View full abstract»

The problem of generating a periodic voltage signal whose Fourier-series representation is given by a band of essentially uniform-amplitude frequency components is examined in this paper. A mathematical background is first established for the purpose of comparing various techniques. Three separate methods of generating the periodic voltage signal are then presented and discussed. View full abstract»

An electronic-flash light source and a calibrated time-delay generator provide a simple and accurate way of measuring the ballistic characteristics of instruments. Several parameters are suggested which can be measured directly by this method and used to specify the properties of an instrument. The method is useful in original design work, since the measured parameters can be related to mechanical... View full abstract»

The design considerations and development of a 12-channel carrier system for trunk and subscriber service are described. The dual-sideband AM (amplitude-modulated) system uses one modulation step only and has a grouped and a stacked frequency allocation for use with and without repeaters respectively. Compandors supplied on an optional basis and the use of high-gain amplifiers make it advantageous... View full abstract»

As advisors to the National Aeronautics and Space Administration (NASA), Lincoln Laboratory performed an analysis of the Mercury beacon-tracking capabilities. Calculations of signal strength to be expected for orbital flights were made. As a result of the marginal signal levels which were computed, a program of improvements was initiated. Suborbital flight-test data were reduced and compared with ... View full abstract»

Project Mercury uses a telemetry-frequency direction finder as an acquisition aid for assisting narrow-beam radars to acquire the spacecraft, but the broad beamwidth of the quad-helix antenna allows multipath reception to degrade tracking accuracy at low elevation angles. Analyses of aircraft and spacecraft tracking results prove that aircraft tests at close range are valid for evaluating orbital ... View full abstract»

This paper describes a microwave communication system of unusual design. Operation is in the 6-gc (gigacycles) frequency range, and the design is to provide for transmission of high-density messages (1,800 voice circuits) or video information. The equipment design is described in terms of the “Terminal Transmitter,” “Through Repeater,” and “Terminal Receiver.” Emphasis is placed on the unique feat... View full abstract»

A mathematical method for estimating the crosstalk loss corresponding to a probability of occurrence of P% at a specific voice frequency is described. The method requires only the information in a given cable specification regarding unbalanced cable parameters and the cable manufacturer's inspection procedure. The method is general and can be used (with minor modifications) to determine crosstalk ... View full abstract»

Operation of the AR matrix (which connects lines and trunks to the register) and of the line matrix (which connects the calling and called stations) is controlled by Originating and Terminating Markers, respectively. "Modular" construction permits adaptation to offices of various sizes; duplicate facilities are used alternately, but each can carry all the load if necessary, without degrading servi... View full abstract»

This paper discusses the design of a switching matrix that is a combination of relays and diode crosspoints, and the design of line and trunk termination equipment associated with it. This switching matrix and termination equipment will have, in addition to normal telephone design parameters (long life, low cost, ease of replacement, etc.), a frequency-range capability of 15 times the 0-4,000-cycl... View full abstract»

The translator provides -pre-translation- to determine the type of call and number of digits to be anticipated. Originating lines are checked for bandwidth rating, class-of-service, and AN (abbreviated-number) calling group identity. The register-sender is furnished a reconstructed directory number on AN calls. Routing translations take into account requested bandwidth, class-of-service, and trunk... View full abstract»

There is a growing demand for accurate and reliable communication channels of various widths, on a call-up basis, for the transmission of analog and digital data. Design features of a nationwide voice co-ordinated communication system specially designed for data transmission are described. View full abstract»