Evaluation of the electrode-amplifier noise in high resolution biological signal acquisition

The noise and the impedance between two non-polarisable Ag-AgCl electrodes were investigated. We proposed a method to compute the equivalent noise at the amplifier input and output using a small number of measurable parameters. It is shown that for a low noise instrumentation amplifier the input noise in the bandwidth of interest (0.1-400 Hz) is in (2-4) /spl mu/V/sub pp/ range.