What are the domestic and international EMC (electromagnetic compatibility) standards for electroencephalogram (EEG) machines?

Electroencephalography (EEG) machines are used to acquire microvolt-level brain signals. The domestic EMC standards are GB 9706.1 and YY 0505, while the international standard is IEC 60601-1-2. These standards impose extremely stringent requirements on the immunity of EEG machines to radio frequency electromagnetic fields and power frequency magnetic fields, as environmental noise can easily drown out useful signals. The reference electrode and grounding design of multi-channel (e.g., 32/64-channel) EEG machines have a significant impact on the common-mode rejection ratio (CMRR). To meet the standards, the electrode input circuit must use a high-CMRR instrumentation amplifier and integrate high-frequency filtering and ESD protection functions at the front end. The isolated communication interface between the device host and the amplifier (e.g., isolated USB) also needs to use an isolation chip and be protected with bypass capacitors and TVS diodes.