602 



SEISMIC METHODS 



[Chap. 9 



represent a coupled system with comparable merits of its members. The 

 latter leads to fairly complex equations, discussed by Wenner* and 

 Schmerwitz. 



The first case, involving an energy transfer in one direction only, has 

 been calculated by Galitzin. When an amplifier representing a unilateral 

 impedance is employed between seismograph and galvanometer, Galitzin's 



0.2 0.4 0.6 0.8 1.0 0.8 0.6 0.4 0.2 



U n ->!<—- ^n ^ 



Fig. 9-107. Frequency response of galvanometer, as a function of tuning factor and 



relative damping. 



solution is applicable, provided that the amplifier action is equivalent to 

 that of a system with simple static magriification. 



Combining eq. (9-97o) with eq. (9-92c) and lumping all constants, so 

 thatV^-V-U/iC = C, we obtain 



h + 26,6 + <.lh = -—^££=^ 

 V (^ojo — 03 ) + 4e w 



of which the steady state solution is 



C 



b = 



sin {cot db 90"* + <p), 



V{c.l-</f + ieW ' ^U - c^y + ^e 



2 2 

 CO 



Xo} sin (oit ± 90° + .^ + ipg) . 



(9-98a) 



** F. Wanner, loc. cit. 



" G. Schmerwitz, Zeit. Geophys., 12(5/6), 206-220 (1936). 



