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BELL SYSTEM TECHNICAL JOURNAL 



to those used in the power amplifiers except that they are of the 

 two-electrode type. The rectifier operates from a 60-cycle, three- 

 phase supply circuit and utilizes both halves of each wave. The 

 two sets of rectified waves are combined by means of an inter-phase 

 reactor which serves to smooth out the resultant current and by 

 distributing the load between tubes of adjacent phases increases the 

 effective load capacity of the rectifier. The ripple is further reduced 

 by the filtering retardation coil and condensers shown. 



Reproductions of the apparatus comprising the transmitter system 

 as described above are given in Figs. 2, 3, 4 and 5. 



Fig. 2 shows the apparatus comprising the low-power stage of the 

 transmitting system. The right-hand rack contains the two weak- 

 power modulating units and the two single-side-band selecting filters. 

 The left-hand rack is the 750-watt amplifier unit. The three radiation- 

 cooled tubes of 250-watt capacity each will be seen near the top. 



