BSL PRO 4 Manual - Biopac

Part C — Analysis Functions 283Signal typeThe Signal type menu contains parameters for specific humanand animal waveform morphologies. All pre-defined andcustom signal types are common to both calculation channelRate (online) and analysis Rate (offline) dialogs. Signal typemodifications affect settings in the Signal Parameters tab only,and do not affect the Output tab settings.Select from six pre-configured signal types or click “New” tocreate, name and save custom setups. This allows quick accessto frequently used Rate detection signals without the need torecreate modified settings. Custom Rate signal types may beadded or deleted in the same manner that channel presets are in other areas of the BSL PRO application.Peak detectBy default, the Peak Detector searches for Positive peaks (upward pointing, such as the R-wave of an ECGsignal) to calculate the rate of a waveform. In some instances, however, you may have to base the ratecalculation on negative peaks (downward pointing). To do this, select Negative peak.Remove baselineThe Remove baseline option applies the optimal high pass filter based on the other settings. This option isuseful when signals have a slowly fluctuating baseline.Auto Threshold DetectWhen the Auto threshold detect box is selected in the Find Rate dialog, BSL PRO automatically computesthe threshold value using an algorithm that accentuates peaks and uses information about the previous peakto estimate when and where the next peak is likely to occur. This threshold detector is typically moreaccurate than a simple absolute value rate calculation function, and is able to compute a rate from data witha drifting baseline and when noise is present in the signal. (For a detailed description of how the calculationis performed, contact BIOPAC Systems, Inc. for the complete Application Note.)• When Auto threshold detect is enabled, the Noise rejection and Window options are enabled.Threshold levelThis option (activated when “Auto threshold detect” is not selected) letsyou enter a threshold level to be used for a simple absolute value ratecalculation function.• The Auto threshold detect option is typically more accurate.Noise RejectionNoise rejection (activated when “Auto threshold detect” is enabled)constructs an interval around the threshold level. The size of the intervalis equal to the value in the “Noise rejection” text box. Checking thisoption helps prevent noise “spikes” from being counted as peaks.• The default is equal to 5% of the peak-to-peak range.BSL PRO Manual