A 200-point analog computer of average transients for electrophysiological measurements.

A 200-point computer of average transients uses capacitors as the memory devices and MOS-FET switches. The averaged wave form is stored exponentially and the memory decays exponentially when that input is removed. The memory exponential time constant (i.e. the number of sweeps averaged) can be varied with one resistor. Read-out to an oscilloscope occurs simultaneously with read-in of each new signal. This linear circuit computes a highly accurate average, even though 10% components are used. It is more cost-effective than commercial digital averagers for many applications and can average evoked potentials, field potentials, weak single units and intracellularly recorded postsynaptic potentials.