352 



BELL SYSTEM TECHNICAL JOURNAL 



and heat capacities from those of the diaphragm with the result that 

 the performance of the receiver was erratic and at a given time was 

 dependent upon the temperature changes to which it had been 

 subjected. 



0. IIJ 



if) m 



R2 



Ri L| i^VVS To mo So r3 m3 



Ksmj 



L2 



Sl 



T) mi S2 



S3 -,— ^A^ 



EQUIVALENT CIRCUIT 



1000 1500 2000 2500 



FREQUENCY IN CYCLES PER SECOND 



Fig. 8 — -Closed coupler response characteristics of the receiver. 



The new receiver is so designed that : 



1. All prominent resonances within the important frequency range 



have been eliminated and the response within this range 

 materially improved. 



2. The effect of changes in temperature has been eliminated. 



