BSL PRO Software Guide - Biopac

Analysis Functions 165MEASUREMENT Area EXPLANATIONFreq (timedomain only)Minimum area:2 samplesUses:Endpoints ofselected areaFor values less than 60 seconds, you will get a value in decimal seconds.For values greater than 60 seconds, you will see an HH:MM:SS formatvalue(See page 736 for details on how to change the horizontal scaling options).Units:Delta T: Seconds (sec.)Delta F: HzDelta X: ”arbitrary unit”Sample data file: “ValidateMeasurements.ACQ”Result: 0.12 sec. (for whole wave).Freq computes the frequency in Hz between the endpoints of the selectedarea by computing the reciprocal of the absolute value of time difference inthat area.The formula for Freq is:FreqWhere: x n1 x1x1,x n- values of horizontal axis at the endpoints of selected area.The information provided by this measurement is directly related to theDelta T and BPM measurements, and is related to a lesser extent to DeltaS measurement. That is, if the Delta T interval between two adjacentpeaks is calculated, the BPM and Freq measurement can be extrapolated.If the sampling rate is known, the Delta S can also be derived.In this example, you can seeDelta T, Freq and BPMmeasurements for theselected area. The Delta Scan also be derived.The graph shows theselected area withmeasurements that describethe same interval in differentterms.IntegralMinimum area:2 samplesNote: This does not compute the frequency spectra of the data. Toperform a spectra analysis, use the FFT function (described on page 7222).Freq (or frequency) is only available in time domain windows.Results: This calculation will always return a positive result.Units: HzSample data file: “ValidateMeasurements.ACQ”Result: 8.33 Hz (for whole wave).Integral computes the integral value of the data samples between theendpoints of the selected area. This is essentially a running summation ofthe data.