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. 



Ri Li i-WS To mo ^o pj ma 



1-2 



M 



S| 



S3 -,— ^A-f- 



*-" r, mi S2 " 



EQUIVALENT CIRCUIT 



!3i 



UJ cf 



5S 



O Q- 

 UJ 

 Q (T 



ijjil 



500 1000 1500 2000 2500 3000 3500 



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. 



