BSL PRO 4 Manual - Biopac

248 BSL PRO ManualTemplate FunctionsThe Template Functions are useful for comparing waveforms. Technically, the template functions providecorrelation, convolution and mean square error transformations of a template waveform against anotherwaveform. To activate the full template menu, select an area and then select set template.NOTE: To determine a level of comparison between two waveforms, use theCorrelation function.All the template functions perform a mathematical operation of the template waveform on the waveform to becompared, move one sample forward, and repeat the multiplication until the end of the longer waveform isreached.Set TemplateUse the following ECG waveform as an example. An abnormality exists in the record. After detecting anabnormality, you should find out if there are other (similar) abnormalities in the record. To do that, you needto select the pattern you’d like to search for, and then compare that pattern to other data sets in the file.Selecting a section of a wave to be used as a template:1) Highlight the section to be used as a pattern.2) Click the Transform menu and choose Set template from the Template functions submenu. Thiscopies the selected portion into a buffer for subsequent template functions3) Select the waveform and position the cursor at the beginning of the data.4) Choose Correlation from the Template functions submenu. The center waveform in the graph belowshows the result of the correlation.Note the higher amplitude peaks where the template data more 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 the record. The first one appears at about 3 secondsand is the one used as a template; the second one appears at about 11 seconds.Visit the online support center at www.biopac.com