HIGH-SPEED OCEAN CABLE TELEGRAPHY 



249 



The output of the ampHfier may be appHed to a siphon recorder or 

 to relays, as desired, and the amount of ampHfication may be adjusted 

 over a wide range to meet the requirements of any particular case. 

 In general the power amplification needed for automatic operation 

 of a loaded cable at its maximum speed is of the order of 10,000,000 

 times, which corresponds to 70 TU. 



The external appearance of the signal-shaping amplifier is shown 

 in Fig. 6. All of the receiving circuit elements shown in Fig. 5 



Fig. 6 — Signal-shaping amplifier 



are contained in its shielded case which is made of ample size so that 

 all of the essential apparatus units within it are readily accessible. 

 Great care has been used in the design and construction of the amplifier 

 unit to protect the circuit elements within it from moisture and to 

 prevent leakage or electrostatic coupling. The output terminals of 

 the amplifier may be connected directly to a siphon recorder or to a 

 suitable relay. However, when the amplifier is used for the operation 

 of relays and multiplex printing telegraph apparatus, there is associated 

 with it an additional piece of apparatus called the relay control desk 



