0-60hz elevated amplitudes

[Guest guest]

Does anyone know why I would be reading elevated amplitudes across the spectrum

(0-60hz)? For the last month or so I've been seeing intermittent, proportional

amplitude increases of 10u - 15u. The impedances are good, 60hz is the lowest

amplitude relative to the rest of the spectrum.

I've changed the type of sensors and used different amps, but I can't figure it

out. The ratios seem fine, but it's as if some of my client have an extra 10-15u

in all bands.

Any ideas are appreciated,

Bill H