400 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1952 



October, 1951, Part II, entitled The DT-2 Microwave Radio System 

 reprinted as Monograph 1921). 



To meet the stringent requirements of the 4,000-mile transcontinental micro- 

 wave relay system, a number of new developments had to be included in the 

 design of the repeater stations. The circuits of these uuattended stations, and 

 how the}' are maintained, are the subject of this article'. 



The Bell System's Part in Defending the Nation. F. R. Kappel". Bell 

 Tel. Mag., 30, pp. 141-152, Autumn, 1951. 



Quickly and accurately checks performance of private or common-carrier 

 p-m or f-m mobile telephone transmitters, such as those used in 30 to 44 -mc 

 highway and 152 to 17o-mc urban service. Measures r-f power output, audio 

 sensitivity, signal-to-noise ratio and harmonic distortion and gives speech 

 intelligibility check in few minutes. 



Mobile Transmitter Testing Set. G. J. Kent . Electronics, 24, pp. 106- 

 109, Nov., 1951. 



A New Electrolysis Switch for Underground Lead Sheath Cable Drainage 

 Systems. V. B. Pike\ Corrosion, 7, p. 1, Oct., 1951. 



A High Temperature Stage for the Polarizing Microscope. E. A. Wood . 

 Am. Mineral, 36, pp. 768-772, Sept.-Oct., 1951. 



A Precise Sweep-Frequency Method of Vector Impedance Measurement. 

 D. A. Alsberg'. Proc. I.R.E., 39, pp. 1393-1400, Nov., 1951. (Mono- 

 graph 1911). 



The impedance of a two-terminal network is defined completely by the inser- 

 tion loss and phase shift it produces when inserted between known sending and 

 receiving impedances. Recent advances in precise wide-band phase and trans- 

 mission measuring circuits have permitted practical use of this principle. Reac- 

 tive and resistive impedance components are read directly from a simple graphi- 

 cal chart in which frequency is not a parameter. The basic principle described 

 promises attractive possibilities in many cases of impedance measurements 

 where present methods are inadequate. 



Electron-Vibration Interactions and Superconductivity. J. Bardeen . 

 Revs. Modern Phys., 23, pp. 261-270, July, 1951. (Monograph 1912). 



The Copper Oxide Rectifier. W. H. Brattain\ Revs. Modern Phys., 

 23, pp. 203-212, July, 1951. 



It is shown that the conductivity in the ohmic part of the cuprous oxide laj^er 

 can be explained with the usual band picture of semiconductors onh* by assum- 



2 A. T. & T. Co. 

 3W. E. Co. 



