18 liEU. SVSTliAf TECIIMC.tL Jdl'KX.II. 



lia\c the wrong inductance or are wroiij^K' sixiccd causes reflections 

 in the manner ciescriherl ai)o\c. 



Ii)i;ai. RkpkativR on an Ii)i;ai. I.ini-; 



Fij;. 4 shows an ideal telephone circuit consisting of two sections 

 of line L\ and L-^ which are free from irregularities and are joined 

 by a repeater R. The remote ends of the line sections are connected 



to terminal apjiaratus A] and .1^ which ha\e impedances which 



B 



Q 



Fig. 4 



s-mc(,thl\' terminate the lines, that is, if either line had originally 

 extended to an infinite distance from (he repeater and had liecn cut 

 to connect it to the terminal apparatus, this apparatus would ha\'e 

 the same impedance as the part of the infinite line which was cut off. 

 The construction of the repeater R is limited onh- by the recjuire- 

 n.ent that if an electric wave arri\cs at the repeater terminals T\ 

 or 7'; o\er either line a similar but larger wa\-e is transmitted from 

 the repeater (i\ er ihi- other line. The gain of the repeater deter- 

 mines the relati\e si/es of the waxes arrixing at and departing from 

 the repeater. 



If now a wave is started at one end of the circuit, for exam[)le -li, 

 it traverses the line Li and is absorbed or dissipated in the portion of 

 the repeater connected to the terminal 'J\. This wave acts upon 

 the internal mechanism of the repeater in such a way as to send out 

 a larger wave which tra\erses the line L^ and i> completeK' dissi- 

 pated in the terminal apparatus A->. 



Ii)i;ai. Kki'KATIck on a Linic C"()NTaimn(. Irrkci i.AKiniis 



Fig. 5 illustrates a line exactly like that of F^ig. 4, except that an 

 irregularit\- Bi (or J5») has been introduced into each section. If a 



B 



Q 



Fik'. .'^ 



wa\e leaves one terminal such as A i, it traverses the line Ai e\entuall\- 

 arriving at the terminal T\ of the repeater R with a ceri.iin striiigih. 

 This wa\e is ; niplificd and traiiMnitted into ihe line /,■_• which it 



