Let the network function be written as :
N(s) = P(s) / Q(s)
Above equation consist of factors of general form where p_{r} and p_{n} are complex frequencies. Their difference is also a complex frequency which can be written as:
Where M_{nr} is the magnitude of the phasor and Φ_{nr} is the phase angle of the same phasor
Thus
All Ms and phase angles can be calculated using the pole zero plot on splane
Procedure for calculation of M and Φ

 Plot the pole zero of the network function
 Measure the distance of M_{1r}, M_{2r} … of a given pole from each zero
 Measure the distance of M_{ar}, M_{br} … of a given pole from each other finite pole
 Measure the angle Φ_{1r}, Φ_{2r} … from each of the finite zero
 Measure the angle Φ_{ar}, Φ_{br} … from each of the finite pole
 Substitute and find the values of K_{r}