Weighted averaging method for evoked potential: Determination of weighted coefficients

The signal-to-noise ratio (SNR) depends on the selection of weighted coefficients when weighted averaging is applied to estimate evoked potentials (EP's). In contrast to Hoke's method based on the consideration of the noise activity in one ensemble being evaluated in terms of statistics, we suggest that the output energy after weighted averaging can be used as an indicator of residual noise energy. The relationship expression between this energy and weighted coefficients is given. With this expression. we discuss the determination of weighted coefficients and propose an algorithm for extraction of EP's. Simulations show our method results in a lower noise energy than Hoke's method and requires fewer ensembles to attain an adequate signal quality.