MODES OF MOT 10 X IX QUARTZ CRYSTALS 



73 



strongly coupled to the fundamental or odd shear. The strong coupling 

 shown between the Xy shear and the second Xy flexure explains why the 

 frequency equations given in section 6.3 for the frequency of flexure and 



240 



200 



8 



32 



16 24 



Y IN MILLIMETERS 



Fig. 6.11 — Shear and flexure resonances in a Z-cut quartz plate. 



shear modes will not give even approximate results if applied to this case 

 for a square crystal. It will be shown later that if account is taken of 

 coupling, the shear mode for a square crystal of this type may be more accu- 



