BSL PRO Software Guide - Biopac

100 Part CCalculation Preset: SmoothingThe Smoothing Calculation functionsonline and permits Median or Meansmoothing. (Smoothing can also beperformed off-line using the smoothingoption of the “Transform” menu). Thisfunction is very useful if you are trying toremove noise of varying types from a dataset.Smoothing factorUse Median valueEnter the number of samples to use as a smoothing factor.The default setting uses Mean value smoothing. Use Mean value smoothing when noiseappears in a Gaussian distribution around the mean of the signal.Click in the box to activate Median value smoothing if some data points appearcompletely aberrant and seem to be “wild flyers” in the data set.Calculation Preset: DifferenceThe Difference calculation returns thedifference between two data samples over aspecified number of intervals. The DifferenceCalculation is useful for calculating anapproximation of the derivative of a data set inreal time.The Difference Calculation dialog allows youto specify the source channel and the numberof intervals between samples over which thedifference is to be taken.SourceIntervalWhen the Source channel contains relatively high frequency data, using the DifferenceCalculation may result in a very noisy response, so it’s best to use the DifferenceCalculation on relatively smooth data.Difference is calculated with respect to the number of intervals between points (rather thanthe number of sample points). For instance, two sample intervals span three sample points:POINTPOINTPOINTIf the Interval is “1” and the source and the output are displayed using LinePlot, then the difference plot will approximate a continuous derivative,shifted one point to the right.Visit the online support center at www.biopac.com