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BELL SYSTEM TECHNICAL JOURNAL 



Uu = — .92 in every branch, which range includes the useful part of a 

 branch. In low pass and band pass wave-filters this total range 

 corresponds to 96 per cent of the theoretical band widths. From (31) 

 there is a minimum y = .9857 at Uk = - .3696, and a maximum 

 y = 1.0198 at Ui.- = — .8297. Of course, other values of the parame- 

 ters in this neighborhood would also be quite satisfactory. They 

 might even be fixed by choosing the frequencies of infinite attenuation 

 in the two half sections. But the above were taken in order to fix the 

 final networks. 



-/. 



-.4 





zk/ 



lb, y 



WinffnM) _ R 



2b, y= ^L = ^^-^_^^^ 



, {171=7250, rri^mn) 



iMg. 14 — -Image impedance characteristics in the transmitting bands — 



(la, 1/)) of fixed terminal transducers, 

 (la, Ih) of comparison transducers. 



(Broken lines are for dissipation with Vu = ± .01 Uk). 



The transfer constants of these fixed terminal transducers of Fig. 

 11 are represented by the general attenuation and phase characteristics 

 of Fig. 13. Here also are shown the corresponding characteristics 

 of two comparison transducers, one of which is made up of a mid-half 

 section each of the "constant ^" and of the shunt .l/-type wave- 

 filters and has the image impedances Wxk and PFu(w). The other, 

 made up similarly, has the image impedances Wik and T4^2a(w). In 



