VIBRATING TELEPHONE DIAPHRAGMS. 



429 



responding approximate motional-impedance distortion circle is 

 marked at OGF, at an angle lagging more than 90° behind the 

 diameter OA. 



On reducing the diaphragm load to 1.2 gm., the distortion loop 

 in Fig. 8 was enlarged to 20.5 ohms at CE; and the distortion at 

 697.5 '~~' is brought slightly nearer to the bottom of the circle. The 

 deduced distortion circle OGF, is also brought to a lag of some- 

 what more than 90° behind the diameter OA. Incidentally a small 

 new and transient distortion appears at H. 



■^//// 



Fig. 9. Amplitude Measurer. 



Summing up the disclosures of the last few figures, it appears 

 that one and the same distortional disturbance in a diaphragm, resi- 

 dent near 700 —', by suitably diminishing the resonant frequency of 

 the diaphragm in successive steps, was made to appear, first as a 

 small loop near the origin on the right-hand side, then as a greatly 

 magnified loop near the diameter, and finally passing off as a small 

 loop near the origin on the left-hand side. The deviations from the 

 main circle are only approximately represented by absorption circles. 

 Moreover, the angle COF , Fig. 7, is approximately equal to the 

 angle CO A. 



