224 



ANNALS NEW YOBK ACADEMY OF SCIENCES 



and it is the purpose of the present paper to show that it may be turned 

 to account to produce improvements in the reception of signals which 

 completely overshadow any of the particular advantages of the audion 

 when used as a simple detector. The ordinary detector circuit is illus- 

 trated by Fig. 13 and the phenomena present therein may be summed up 

 diagrammatically by the curves of Fig. 14. It will be seen from these 

 that the radio frequency oscillations present in the wing circuit of Fig. 

 13 with the ordinary audion are necessarily small, and also that they are 

 of no value in producing a response in the telephones ; but by providing 

 means for increasing their amplitude and means for utilizing them to 

 reenforce the oscillations in the grid circuit, it becomes possible to pro- 

 duce some very remarkable results. 



Eeenporcement of Radio Feequency Oscillations by the Audion 



There are two ways of reenforcing the oscillations of the grid circuit 

 by means of those in the wing circuit. The simplest way perhaps is to 



^J8^ 



Fig. 16 



couple the two circuits together in the manner sliowji in Fig. 16. This 

 is essentially the same as Fig. 13, but modified by the introduction of the 

 inductively coupled coils Lo and Lg in the grid and wing circuits re- 

 spectively and by the condenser Co, which forms a path of low impe- 

 dance across the telephones for the radio frequencies. In such a system^ 

 incoming signals set up oscillations in the grid circuit which repeat into- 

 the wing current producing variations in the continuous current, the 

 energy of which is supplied by the battery B2. By means of the coupling 

 Ti/o, some of this energy of the wing oscillations is transferred back to 

 the grid circuit, and the amplitude of the grid oscillations thereby in- 



