The Bell System Technical Journal

An attempt is made to classify theoretically paramagnetic resonance signals of inhomogeneously broadened lines occurring under various experimental conditions. The theoretical predictions are checked experimentally. Special emphasis is given to cases in which T1is long, and to cases in which the adiabatic condition γH$$ $rQ dH/di is violated. View full abstract»

A new radar technique has been developed that provides a solution for the conflicting requirements of simultaneous long-range and high-resolution performance in radar systems. This technique, called Chirp at Bell Telephone Laboratories, recognizes that resolution depends on the transmitted pulse bandwidth. A long high-duty-factor transmitted pulse, with suitable modulation (linear frequency modula... View full abstract»

Radar systems that yield simultaneous information regarding the range and velocity of a target would be useful in certain applications. A discussion is presented of some fundamental limitations on simultaneous range-velocity determination in terms of ambiguity diagrams, with the aid of a quantum mechanical analog to the Wigner distribution function. A sequence of signals is found in which the sign... View full abstract»

The TJ radio relay system is a broadband microwave facility that operates in the 10,700-to 11,700-mc common carrier frequency band. It has been specifically designed for short-haul transmission of either multichannel telephone or television circuits. Transmission performance and the over-all system description are presented, as well as some early field applications. View full abstract»

The reduction and control of message circuit noise requires that its effects be quantitatively characterized. This is achieved by measuring some physical attribute of the electrical noise such that two noises that are judged to be equally interfering are assigned approximately equal numerical magnitudes. To give meaning to such magnitudes, the scale of measurement is related by way of subjective a... View full abstract»

A new message circuit noise measuring set is described. The instrument is an easily portable, visual-indicating and direct-reading device with which rapid and accurate noise measurements may be made. The set is fully transistorized and battery powered, small in size and light in weight. It can be used for bridging, terminating and noise-to-ground measurements with a variety of plug-in weighting ne... View full abstract»

In the process of growing an oxide on doped silicon, electrically active impurities near the silicon/silicon dioxide interface are redistributed according to the diffusion coefficients and the distribution coefficient of the impurity between the oxide and the semiconductor. An analysis of the phenomenon predicts that single-junction or two-junction material can be obtained by oxidation of the surf... View full abstract»

A general method is presented for synthesizing driving-point impedances using RC networks and active elements. The procedure realizes any real rational driving-point function and leads to rather simple structures. Only one active device, a negative-impedance converter, is required. The synthesis of biquadratic impedance functions is considered in detail. View full abstract»

Pressure at the interface of the inner conductor and the dielectric of the armorless ocean cable is experimentally determined for plane stress boundary conditions. Polyethylene outer and steel inner concentric cylinders are considered as a mechanical model of the ocean cable. Equations are derived to give the pressure at the interface for plane stress and plane strain conditions. It is found that ... View full abstract»

Many types of missiles are guided by a finite set of distinct commands radioed from the ground in the form of a time-sequence of RF pulses. The command information is contained in the n − 1 time spacings between successive pulses in a group of size n, and is encoded and decoded by means of multitapped delay lines combined with AND gates. This paper discusses the problem of encoding command informa... View full abstract»

From the user's point of view, what are the desirable characteristics of pushbuttons for use in 500-type telephone sets? The studies reported bear on this question and also on questions of how people process information when keying telephone numbers. Four categories of design features were studied: key arrangement, force-displacement characteristics, button-top design and central office factors. T... View full abstract»