How is noise filtered in instrumentation systems?

Noise filtering uses multiple techniques: Anti-alias filters (before ADC to prevent high-frequency fold-over), low-pass filters (remove high-frequency noise), notch filters (remove specific frequencies like 50/60 Hz mains), averaging/integration (reduce random noise by sqrt(N) for N samples), shielding (block electromagnetic interference), twisted pair wiring (cancel induced voltages), differential signaling (common-mode noise rejection), and grounding (provide low-impedance return path). Digital filters can implement complex responses without component variations. Filter design balances noise rejection against signal bandwidth and phase distortion.