﻿1874.] L. Schwendler — On the general Tlieory of Duplex Telegrapliy. 13 



'^ (t' + dO(a'+ b^+ gO + b'(a' + gO 



and N" an expression identical in form with N'. 



Further by Q^ we understand the force which acts on the receivin"* 

 instrument of station I, when both stations are sending simultaneously : 

 Duplex Signals, 



This force is again proportional to the current which under these 

 circumstances passes through the receiving instrument g' of station I, 



This current can be expressed by 



n 



and therefore : 



Q'oc E/^ — (r'<^' 



or ' being the current actually in the line at point 1 when both stations are 

 sending simultaneously ; and this current, being the algebraical sum of two 

 currents may be either +, 0, or — . We will suppose that cr' contains 

 the sign itself. 



Further we have 



n'= (b/ + d^ + f) (a^ + gO + b' (f^ + d') 

 and <^ ' is a function which becomes indentical which i// Mf we put 



w' + y8' == f . 

 Therefore the two functions D and S are for the Bridge method 

 (station I) most generally expressed as follows : 



*&" 



E/ N" J A' 



^'^^'W^' '^^' ^^^^'^ 



andS' = E"^/./^^-^^ + cr'<A' (IVO 



and similar expressions will be obtained for station II, namely 



E'' N' 1 A" 

 Ti" — — —- - ■ f IIF^ 



andS" = E'J,/f-^'+cr''cA" (IV") 



