ZERO TEMPERATUBE COEFFICIENT QUARTZ CRYSTALS 



367 



400 

 350 

 300 



250 



UJ 



< 200 



I 

 o 



Z 150 

 O 



100 



50 







-50 



-100 



-150 



-200 



-120 -100 -80 



-60 -40 -20 20 40 60 80 100 120 

 TEMPERATURE IN DEGREES CENTIGRADE 



140 160 180 200 



Fig. 1 — Frequency temperature characteristics of AT type crystals. 



200 



-200 



■400 



-600 



-800 



-1000 



a -1400 



-1600 



1800 



-80 -60 -40 -20 20 40 60 80 100 120 140 160 180 200 



TEMPERATURE IN DEGREES CENTIGRADE 



Fig. 2 — Frequency temperature characteristics of BT type crystals. 



