Above equation consist of factors of the 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 s-plane

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