the unknown load r 2 must be determined in a first step to this end the equations for ports iii and iv which are terminated by known reflection factors r 3 and r 4 must be eliminated from the network matrix the method described below with reference to fig3 is used for this purpose in this figure the incoming wave parameters are denoted by a sub u03bd the outgoing wave parameters by b sub u03bd the clamping voltages by u sub u03bd and the currents by i sub u03bd where in each case 1 u2266 u03bd u2266 n and u03bd u2260 m the method permits an n port in the concrete case here n 4 1 whose mth port is provided with a known terminating element rm to be used to calculate a remaining n 1 port by eliminating the equations for the mth port a scattering matrix s describes a system of equations of type equ1 the known reflection factor r m which is connected to a port m necessitates that a m r m b m that is to say equ2 substitution in the remaining equations yields equ3 these n 1 equations describe an n 1 port network with a scattering matrix s 39 which no longer contains the mth port its scattering matrix elements are thus in the following representation we shall choose u03bd 39 u03bd and u03bc 39 u03bc in order to preserve unique port designations however it would also be possible for the purpose of simplifying the programming to reselect the indexing of the remaining ports for example in.