FIR/IIR Filter Frequency Response

H(e^jw) Magnitude-Phase Response & Pole-Zero Plot

Pole-Zero Plot (z-plane) Drag poles/zeros to edit
Magnitude Response (dB)
Phase Response
Group Delay
Zeros
Poles
Unit Circle
-3dB Line

Presets

Filter Parameters

Filter Type
Filter Order 5
Cutoff Frequency 0.25pi

Interaction

Double-click: add | Right-click: remove | Drag: move

Filter Statistics

Type
-
Order
-
Zeros
-
Poles
-
Stability
-
-3dB Cutoff
-
Max Ripple
-
Stopband Att.
-
FIR/IIR
-

About Digital Filters

FIR (Finite Impulse Response) filters have only zeros and are always stable. IIR (Infinite Impulse Response) filters have both poles and zeros, enabling sharper selectivity with fewer coefficients but requiring stability analysis.

The transfer function H(z) = B(z)/A(z) describes the filter in the z-domain. Evaluating on the unit circle z = e^(jw) gives the frequency response.

Pole-zero analysis: zeros create frequency nulls, poles create peaks. All poles must lie inside the unit circle for stability.

Applications include audio equalization, biomedical signal processing, communications, image processing, and control systems.