BSL PRO Software Guide - Biopac

208 Part DTemplate FunctionsThe Template Functions are useful for comparing waveforms. All the template functions perform amathematical operation of the template waveform on the waveform to be compared, move one sample forward,and repeat the multiplication until the end of the longer waveform is reached. Technically, the template functionsprovide correlation, convolution and mean square error transformations of a template waveform against anotherwaveform.Note: To determine a level of comparison between two waveforms, use the Correlationfunction.Set templateIf you detect an abnormality, you should find out if there are other (similar) abnormalities in the record. To dothat, you need to select the pattern you’d like to search for, and then compare that pattern to other data sets in thefile. You can use the Zoom tool to inspect the abnormalities more closely.Establishing the template:1) Highlight the section to be used as a pattern.2) Choose Set template from the Transform >Template functions submenu. This copies theselected portion into a buffer for subsequenttemplate functions.3) Select the waveform and position the cursor at thebeginning of the data.4) Choose Correlation from the Template functionssubmenu.The center waveform in this graph shows the result ofthe correlation and mean square error functions:Note the higher amplitude peaks where the template datamore closely matches the waveform. The lowerwaveform illustrates the mean square error function,which is similar to the correlation function.This indicates that there are two abnormal beats in therecord. The first one appears at about 21 seconds and isthe one used as a template, the second one appears atabout 33 seconds.Remove MeanVisit the online support center at www.biopac.com