CABLE DESIGN AND MANUFACTURE 



211 



core caused by foreign particles which escaped detection by the other 

 mechanical and electrical tests made on the core. 



As discussed under the section on jointing, the core lengths were as- 

 sembled and joined together to form a repeater section of cable. In 

 general, an effort was made to produce the core for a repeater section 

 of cable on a particular strander, extruder, and armoring line, and to 

 join the lengths together in the order of manufacture. Practical difficul- 

 ties such as the fact that the outputs of two stranders were required to 

 supply one extruder made it impossible to achieve this objective in all 

 cases. 



Capacitance deviations from the desired nominal resulted from a 

 variety of causes, such as inaccurate control of the temperature of the 

 water in the core cooling troughs and improper adjustment of the control 

 apparatus. To minimize the reflection which would result from joining 

 together two lengths of core of widely different capacitances, cores were 

 not joined together if their measured ac capacitances differed by more 

 than 0.3 per cent. When such capacitance differences did exist, the core 

 length involved was removed from its normal sequence and placed in a 

 position near the middle of the repeater section. 



Because the taping and armoring processes were combined in one 



€ 



CABLE UNDER TEST 



3E 



ISOLATING 

 TRANSFORMER 



MATCHING 

 TERMINATION 



SPLITTING 

 PAD 



\ 



SERIES 



MATCHING 



TERMINATIONS 



SWITCHED AT 



POWER FREQ 



RATE 



FINE 



GAIN 



CONTROL 



CRO 



OSCILLATOR 



CONSTANT 



VOLTAGE 



REGULATOR 



t 



STANDARD 

 FREQUENCY 

 GENERATOR 



t 



TUNED 

 DETECTOR 



CONSTANT 



VOLTAGE 

 REGULATOR 



11 



AC SOURCE 



AC SOURCE 



Fig. 10 — Simi)lified block diagram of cable attenuation measuring set. 



