DEVELOPMENT OF A HANDSET FOR TELEPHONE STATIONS 261 



the receiver to the transmitter in the frequency range where the in- 

 struments respond most readily. 



A further and perhaps a major factor in eUminating the danger of 

 howling is to be found in the characteristics of the transmitter. The 



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Fig. 10 — -Use of gauge for head measurements. 



response of a transmitter to bodily movement of the whole structure is 

 of coursv^ very different from its response to acoustical pressures, and 

 depends largely on the mechanical impedance of the diaphragm and its 

 supporting structure. The extremely light and highly damped dia- 

 phragm of this transmitter is ideally suited for minimum response to 

 mechanical vibration. 



