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BELL SYSTEM TECHNICAL JOURNAL 



where k the electromechanical coupling is given by 



k = du 



The two crystal cuts and their constants are given in Table IV. 

 Only the numerical value and not the sign are determined for di2 



Table III 



(A.28) 



Table IV 



Table V 



The variation of dn a,sa, position of angle has been shown to be® 



dn = -h[dn(l + cos 2A2) + du sin 2.42] (A.29) 



The two values of dn of table IV are satisfied by 



dn = -6.76 X 10-8; du = +2.56 X IQ-^ (A.30) 



^ See "Electrical Wave Filters Employing Quartz Crystals as Elements," W. P. Mason, 

 B. S. T. J., Vol. XIII, 405 July 1934). 



