AUTOMATIC PRINTING EQUIPMENT 423 



the vibrating segments V and the vibrating brush of the distributor. 

 The distributor segments are shown developed for the sake of clearness. 

 Disregarding the line winding for the moment, the passage of the 

 vibrating brush over segment Ci, when the relay armature is resting 

 against the negative contact, causes the vibrating condenser to be 

 negatively charged by the battery Ei, and as the brush continues its 

 rotation and passes upon segment Vi, the charged condenser is dis- 

 connected from the charging circuit and is connected to the vibrating 

 winding through which it immediately discharges in the proper 

 direction to cause the relay armature to be moved against its opposite 

 or positive contact. This change in the position of the relay armature 

 connects all of the "C" segments to positive battery, so that the 

 passage of the brush over segments C2 and V2 in succession causes 

 the condenser first to be positively charged, then to discharge through 

 the vibrating winding which restores the relay armature to its former 

 position against its negative contact. This cycle of operations will be 

 repeated as long as the brush rotates and the rate of vibration can be 

 made to coincide exactly with the frequency of the transmitted signals 

 by suitably arranging the vibrating brush so as to be corrected from 

 the incoming signals in a manner similar to that employed in the 

 standard multiplex system. ^^ The armature of the vibrating relay, in 

 addition to controlling the polarity of the charge upon the vibrating 

 condenser, controls the polarity of a battery applied to the receiving 

 brush which distributes the received and corrected signalling impulses 

 to the selector magnets of the receiving printer. In practice an 

 intermediate relay, not shown in the figure, is employed between the 

 armature of the vibrating relay and the receiving brush. 



The line winding of the vibrating relay is connected in the amplifier 

 circuit in the direction which will cause its armature to move toward 

 its positive contact in response to incoming signalling impulses of 

 positive polarity and vice versa, and as the amplitude of the current 

 in that winding is adjusted to be approximately equal to that of the 

 vibrating impulses, the effect of impressing the amplified and partially 

 corrected positive impulse D upon the line winding at the time the 

 vibrating brush is passing over segment Vi would be only to aid the 

 condenser discharge current in reversing the position of the relay 

 armature. Every received impulse of unit length and the current 

 during the first interval of unit length in every sustained pulse will 

 produce the same result as shown at D, E, F and //, but the effect of 

 current in the line winding due to the second and all succeeding time 

 units of every sustained pulse will be neutralized, as shown at G, I 



11 T. H. Bell, loc. cit. 

 28 



