matlab-design-digital-filter

What problem does it solve?

This Skill prevents incorrect or fragile digital filter designs by guiding MATLAB-based development with rigorous preflight checks, validated architecture selection, and consistent Hz-aware verification.

Core Features & Use Cases

• Digital filter design with guardrails: Designs FIR/IIR lowpass, highpass, bandpass, bandstop, and notch filters using MATLAB Signal Processing Toolbox and DSP System Toolbox while enforcing critical gotchas (SampleRate pinning, SOS stability, and correct API parameterization).
• Architecture selection for efficiency: Uses transition-band metrics (trans_pct/trans_bw) to decide between single-stage designs, efficient narrow-transition alternatives (multirate/IFIR/multistage), and when to ask clarifying questions (mode and phase constraints).
• Validation and comparison workflows: Verifies designs with freqz and Filter Analyzer (magnitude and group delay), including special handling for filtfilt’s effective squared magnitude behavior.

Quick Start

Ask: “Design a zero-phase offline lowpass filter in MATLAB for Fs=48000 Hz with Fpass=4000 Hz, Fstop=5000 Hz, Rp=0.1 dB, and Rs=80 dB; include the MATLAB code and verify it with freqz and Filter Analyzer.”