# Input P/Z¶

Fig. 9 shows a typical view of the P/Z tab where you can view and edit the filter poles and zeros. Pole / zero values are updated every time you design a new filter or update the coefficients.

In the top row, the display of poles and zeros can be disabled as an update can be time consuming for high order filters ($$N > 100$$).

## Cartesian format¶

Fig. 9 Screenshot of the pole/zero tab in cartesian format

Poles and zeros are displayed in cartesian format ($$x$$ and y) by default as shown in Fig. 9.

## Polar format¶

Fig. 10 Screenshot of the pole/zero tab in polar format

Alternatively, poles and zeros can be displayed and edited in polar format (radius and angle) as shown in Fig. 10. Especially for zeros which typically sit on the unit circle ($$r = 1$$) this format may be more suitable.