562 lUll.L SYSTEM TIICIIXICAL JOURNAL 



material aid in the application of the theory. There are also given 

 the results of some experiments made on cable circuits in which 

 comparison is made between the impedance departures of the circuits 

 as obtained by direct measurement with the departures as computed 

 from data coxering the indi\ifhiai irreiiiilaritics. These inipt'danre 



G. E 



Kit;. 1 



departures are expressed as "return losses," the meaning of which 

 is explained below. The agreement is shown to be dose enough to 

 constitute a gootl check as to the correrlness of the iinderKing tiu'ory. 



M.\GNITUDE OF RKKI.KCTIiU CURRKNT 



In Fig. 1, are shown three regular ' telephone lines of the .same 

 type i)eginning at a certain point A. The first line Li pa.sses througli 

 anotiier point B and continues on to infinit\\ The second line L-j 

 terminates at B where it is connected t<i an impedance Zt whicii 

 differs from the characteristic impedance Z„ of the three lines, thus 

 constituting an irregular termination. The third line L3 also termi- 

 nates at B where it is connected to an impedance Z/ and a generator 

 G of zero impedance whose ])in-pose will l)e described later. At the 

 sending end A each line is pro\ided with one of three identical genera- 

 tors, G\, G>, Ci, ha\ing an impedance e(|ual to Zg the characteristic 

 impedance of the line. The internal voltages of these generators 

 are all e()ual and represented b\- li. The generator Gi impresses a 



' In this paper the term "reRiilar" iinpliis tliat a telephone line is free from elei- 

 triral irregularities. 



