ABSTRACTS OF TECHNICAL ARTICLES 509 



output digit register. This system performs the functions of photoelectric en- 

 coding, pulse regeneration, digit storage, reflected-to-natural binary translation, 

 and digit shifting by means of circuits using transistors and other semi-conductor 

 devices. The model occupies a volume of about \i cubic foot, weighs seven 

 pounds, and consumes 16 watts of power. 



Comparison of Recording Processes. J. G. Frayne^, I.R.E., Trans., 

 PGA-7, pp. 5-8, May, 1952. S.M.P.T.E., JL, 59, pp. 313-318, Oct., 

 1952. 



The three common forms of sound recording may be classed as mechanical 

 (disk), photographic and magnetic. All three methods are in common use today 

 and each is employed in a field for which it appears to be pecuharly fitted. The 

 purpose of this article is to examine briefly the factors which determine the 

 fidelity of each method. By fideUty we mean how true the tonal range can be 

 reproduced, the amount and nature of h'armonic distortion present, the signal- 

 to-noise ratio possible with each method, and the amount of wow or flutter that 

 may be expected under average conditions of reproduction for each recording 

 process. 



Transistor Shift Register and Serial Adder. J. R. Harris^ I.R.E., Proc, 

 40, pp. 1597-1602, Nov., 1952. 



A small set of basic functions, such as binary memory and elementary binary 

 logic, can be remarkably versatile; such functions are important in switching and 

 computing. This paper describes a piece of computing equipment which can store 

 a pair of binary numbers and add them, producing the sum a digit at a time. 

 The equipment is built from a basic set of functional blocks, all of which are de- 

 signed around transistors. This set of building blocks consists of a binary cell, a 

 pulse amplifier, a pulse amplifier w^ith delay, and logic circuits. The binary cell is 

 a flip-flop; amplifiers are monostable circuits, and logic is performed in diode 

 gates. Some interesting special features arise from the use of transistors. These 

 features are discussed and the designs are evaluated. 



Charge Transfer and the Mobility of Rare Gas Ions. J. A. Hornbeck^ 

 Jl. Phys. Chem., 56, pp. 829-831, Oct., 1952. 



Ion-atom collisions in the rare gases between an atomic ion and a parent gas 

 atom, such as Ne+ and Ne, involve quantum mechanical symmetry effects which 

 though rigorousty inseparable have been fisted as (a) a force of resonance attrac- 

 tion, (b) a force of resonance repulsion, and (c) charge exchange. Drift velocity 

 measurements at high fields show that this compficated interaction may be rep- 

 resented to a good approximation by the hard sphere model of kinetic theory in 

 which the collision cross section is several times the viscosity cross section of the 

 atoms themselves. 



Broad Band Matching with a Directional Coupler. W. C. Jakes^ I.R.E., 

 Proc, 40, pp. 1216-1218, Oct., 1952. (Monograph 2033). 



^ Bell Telephone Laboratories. 

 ^ Westrex Corporation. 



