104 PIU.L SYSTEM TllCHSlCAL JOURXAI. 



Substituting tin- al«>\e xalut's of /"i./o and/, in formula (94) we olnain 

 forZ, 4Z» 



_'LV (hV 



2, \f 



ar & 



+1 



From lliis last expression the attenuation and phase characteristics 

 may be plotted from formulae (22) and (23) or from Figs. 11 and 12. 

 The attenuation and phase constant ch.iracteristics are shown sym- 

 bolically as characteristic 10 of Fig. 44. This structure has unusual 

 attenuation properties which h.i\'e already been discussed. 



I'Vom e(|uali(»n ((i) and the \alues of Z\ and Z2, in (92) and (91}), 

 the mid-series image impedance (Zo), at the niid-freijuencN', is 



Since the mid-suries image imjjeilance, at an\- frequency, is the 

 same as that of filter section 3 — 3, we ha\e: 



where /m is the miil-lre(|uency (/m = \//iA>'. ^'^ i)efore. 



The prototyjK- is not capable of mid-shunt termination, hence, its 

 hypothetical mid-shunt impedance characteristic will not be derived. 



From the preceding formulae, explicit expressions m\v be derixed 

 for the values of A,, C'l, Lq and ( •.. 



, Zotn' 



T -Zo l-m'» 



< if) +1 



