Signal Averaging > Introduction
Many electrophysiological signals have poor signal-noise ratios, making it difficult to obtain accurate measurements from individual records. However, if a signal can be made to occur repeatedly, digital signal averaging techniques can recover the signal waveform from the background noise.
The signal average of a series of records is generated by computing the average of each corresponding sample within the records. For a set of N records, consisting of samples, yi, (i=1,n) the average record consists of n samples, and is given by.
The location of signals within the record sometimes varies from record to record, due to imperfections in the detection of spontaneous signals or fluctuations in stimulus latency. In such circumstances, averaging corresponding sample points within the record would result in a distorted signal average. This problem can be avoided by aligning the signals by the mid-points of their rising phases before averaging.