COUPLING NOISE:

Coupling comes from nearby sources producing magnetic or electric fields. The biggest source of inductive and capacitive coupling interference comes from the pulsed magnet producing a noise signal with a peak in the fournien transform near 40 Hz (see Magnetic Field Profile). Because our experiments are placed inside pulsed field magnets, this is always huge and one of the most difficult to overcome especially in the case of low resistance measurements.

To minimize pulsed magnet infererence, make sure that the wires connecting instruments do not have a lot of open-loop area perpendicular to the magnetic field. Cables should be as short as possible and multiple cables should be held or twisted together to minimize the loop area. Also, all cables should be moved as far away as possible from magnetic field sources. This includes all the cables leading out from the probe to the panel that leads to the data recording instruments.

60 Hz noise from the power isolation transformers can also enter the experiment via inductive coupling, and computer displays (CRT and the backlight of LCD) are strong sources of capacitively coupled interference.