458 



BELL SYSTEM TECHNICAL JOURNAL 



For the purpose of identification the plate cut at +31° has been 

 designated as the ^C-cut and the plate cut at — 60° the BC-cut. 

 Crystal plates having these orientations have been made up and 

 tested. It is evident from the frequency-temperature and frequency- 

 thickness characteristics of both cuts that a simplification of the 

 frequency spectrum results from the reduction in coupling to secondary 



9000 

 8500 

 8000 

 7500 

 7000 



Q 6500 



z 

 o 



JJj 6000 



cc 



LlJ 



Q. 5500 



01 

 UJ 



d 5000 



>- 

 u 



1 4500 



UJ 



O 



5 4O00 



X 



o 



V 3500 

 O 



2 

 UJ 



D 3000 

 Cf 



UJ 



(X 



"- 2500 



2000 



1500 



1000 



500 



20 24 28 



32 36 40 44 48 52 56 60 64 

 TEMPERATURE IN DEGREES CENTIGRADE 



68 



72 76 



P'ig. 3 — ^Frequency-temperature characteristics of AC-cut and Y-cut plates of same 



frequency and area. 

 Frequency 1600 KC. 

 Dimensions: 



Y-cut y =1.22 mm. x = 38 mm. c = 38 mm. 



AC-cut (31°) y' = 1.00 mm. x = 38 mm. z' = 38 mm. 



