METHOD AND CIRCUIT ARRANGEMENT FOR FILTERING PERIODIC NOISE SIGNALS TO THE EVALUATION OF PRODUCED RESPONSE BY MEANS OF AVERAGING

摘要

A computer processes a set of signals picked up from an examined subject by means of electrodes, passed via an amplifier . The set of signals includes an average evoked response reacting to external stimuli, combined with periodic stray signals. The periodic signals are eliminated during the averaging proc edure in proportion to the number (N) of sweeps of the averaging procedure. This results in an N-fold reduction in stray signals by the introduction of a phase shift. - Either the cycles of the external stimuli and initial phases of the periodic stray signals at the beginning of two successive periods, have a phase difference, or the beginning of two successive sweeps of the averaging procedure, may have the phase difference.