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BELL SYSTEM TECHNICAL JOURNAL 



and attenuation diagrams in Fig. 2 illustrate some of its properties. 

 Especially is it to be noted that the infinite attenuations, occurring 

 where the series impedance is anti-resonant, take place at frequencies 

 f al and f a i which are not arbitrary but depend entirely upon the 

 critical frequencies / , f u / 2 and / 3 . 



o f r, r, f, 



Fig. 2 — "Constant k" Low-Band-and-High Pass Wave-Filter 



It may be added that in "constant k" wave-filters every internal 

 transmitting band is a confluent band formed by the junction of two 

 bands occurring separately in a wave-filter of higher class but with 

 the same configuration of elements. 



Summarized, the above procedure for "constant k" wave-filter 

 design is: 



(1) Obtain synthetically a structural form for the series impedance, 

 Zi k , from either the transmission or attenuation requirements; 



