VIBRATING TELEPHONE DIAPHRAGMS. 



427 



that, at least to a first approximation, the distortion consisted 

 of a negative or absorption circle, of the same general character as 

 the main impedance circle, but which is swept over much more 

 rapidly. The constants A', m' , r' and / of this absorption circle 

 were capable of being roughly determined. 



From the Impedance and 

 Velocity Circles it is seen 



that, if the Impedance 



Circle has a reentrant 



loop, the diaphragm 



Velocity/ Circle has one 

 also. 



Telephone F?ece:ivep B 

 Load atCenfer, l.3gm. 



impedance: 



10 5 O /O 20 30 ohm 



linilMiil I I I 



vELociry 



z 



I .5 I 



I""'""' ' 



3 cm/sec 



Resistance "■*'' '^° -^'^ 'i^ <^ '^ ^° -^^ ■^^ ^'^ ^° 

 Fig. 7. Distorted Impedance and Velocity Circles. Distortion Loop Setting 



in the Left. 



By still further increasing the load on the diaphragm to 1.3 

 gm., and thus bringing its resonant frequency to 680 -—', or below 



