What are the common noise sources in instrumentation systems and how are they mitigated?

Common noise sources: electromagnetic interference (EMI from motors, drives, radio - mitigate with shielding, filtering), conducted noise (power supply ripple, ground noise - use isolated supplies, proper grounding), thermoelectric voltages (dissimilar metals - use same materials throughout), 1/f noise (low-frequency, inherent to electronics - chopper-stabilized amplifiers), and quantization noise (ADC resolution - increase resolution or oversample). Mitigation techniques: proper shielding and grounding, differential measurements, filtering, physical separation from noise sources, and twisted pair cables. Systematic approach: identify noise characteristics then apply appropriate mitigation.