Fig. 12.1. Magnetic signals produced by various sources.
Biomagnetic signals: MCG = magnetocardiogram, MMG = magnetomyogram, MEG = magnetoencephalogram, MOG = magneto-oculogram
Noise fields: static field of the Earth, geomagnetic fluctuations, laboratory noise, line frequency noise, radio frequency noise
Equivalent input noise: commercial flux-gate magnetometer, ring-core flux-gate (NASA), induction coil magnetometer, SQUID-magnetometer.
Thermal noise fields: eddy current shield, the human body.