90 



BELL SYSTEM TECHNICAL JOURNAL 



RIGHT HANDED 

 CRYSTAL 



X (+BY compression) 



Fig. 11 — Angular system for locating the axis of shear of high-frequency 

 crystals with two rotations. 



specify the position of the plate since, for a low-frequency shear crystal, 

 rotating the plate around its shearing axis will change the 555' constant 

 and hence the frequency and temperature coefficient of the plate. If we 

 let the position of the plate with respect to the crystalline axes be de- 

 noted by the angles, 6, 97 and 7, measured as shown on Fig. 12 it can be 



RIGHT HANDED 

 CRYSTAL 



4fi 



X (+ BY compression) 



Fig. 12 — Angular system for locating low-frequency shear crystals 

 with three rotations. 



