Group Delay

Introduction Frequency magnitude plots rarely reveal phase behavior. Yet in real-time DSP systems, phase distortion and group delay often determine overall system performance. Applications sensitive to timing include: control loops audio monitoring feedback systems instrumentation pipelines Ignoring phase characteristics can destabilize otherwise correct magnitude designs. What Is Group Delay? Group delay measures: how long different frequency components are delayed In FIR linear-phase filters: delay is constant predictable In IIR filters: ...

Introduction In real-time DSP systems, filter design is not purely a frequency-domain problem. Every additional tap, pole, or processing stage introduces computational cost and delay. Engineers frequently face questions such as: Why does a sharper filter increase system latency? When does FIR linear phase become impractical? How many notches are safe in real-time pipelines? When should I prefer IIR over FIR? This article explains the tradeoffs between latency, filter complexity, and stability in practical DSP systems. ...