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BELL SYSTEM TECHNICAL JOURNAL 



is provided in which a certain amount of the carrier is taken at the 

 end of the intermediate frequency stages, ampHfied and rectified. The 

 resulting d-c. current produces a voltage drop across a resistance, which 

 is applied to thegridof the first detector in such a manner that an increase 

 in the intermediate frequency output brings about a reduction in the 

 total set gain and vice versa. Manual gain control for following wide 

 changes in the received fields is accomplished by variation of the 

 voltages applied to the grid and the screen of the first detector. 



The voice-frequency equipment, in addition to the desk telephone 



H F FILTCR 



i^'' OET. ANO BEATING OSC. 



Fig. 14 — Ship receiver schematic diagram. 



set located in the subscriber's booth, comprises a technical operator's 

 position located adjacent to the ship's receiver, and an attendant's desk 

 located on a lower deck in a room adjacent to the subscriber's booth. 

 The control equipment consists of repeaters, volume control devices, 

 and volume indicators, by means of which the levels of the incoming 

 and outgoing signals can be properly adjusted. Keys are provided 

 which enable the technical operator to talk either over the radio circuit 

 or to the ship subscriber. The booth attendant has facilities by which 

 he can talk either to the subscriber or to the control operator and has a 

 connection with the ship's telephone system for the purpose of locating 

 persons on the ship and calling them to the radio telephone booth. 



