BSL PRO 4 Manual - Biopac

122 BSL PRO ManualTimed Reset is a new option for the Integrate operation in BSL PRO. This operation computes a straight sumof the source data points and resets this sum after a fixed amount of time has elapsed. This periodic integral isused in several types of analysis, such as EMG analysis where it can generate an EMG signal or estimate thepower in fixed time intervals.The time interval at which the integral resets to zero may be specified in seconds or in samples.Timed reset functionality may also be used in calculation channel presets and by the Mac OS X Integrateautomator action.Smoothing CalculationThe Smoothing Calculation functions online in real time and is very useful ifyou are trying to remove noise of varying types from a data set.1. Choose MP > Set Up Channels.2. Click the Calculation tab.3. Check an Acquire box for the Calculation channel you want tocontain the filtered data. You may also check the Plot and Valuesboxes as appropriate for each channel.4. Click the Preset pull-down menu and select Smoothing.5. Click the Setup button in the Input Channels dialog to generate the Smoothing dialog.(Off-line Smoothing is available under Transform > Smoothing.)SourceSource is a pull-down menu of the available channels.Smoothing factor enter the number of samples to use as a smoothing factor.Smoothing method This calculation channel provides real-time Mean (default) or Median smoothing.Mean value The default is mean value smoothing. Use Mean value smoothing when noise appears ina Gaussian distribution around the mean of the signal.Use Median value 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.For a given sequence of wave data, x = {x 1 , x 2 ,...,x n }, Median value smoothing will sortthe sequence and extract the median equivalent to the recommended NIST (NationalInstitute of Standards and Technology) formula: n is odd: median is the center element of the sorted list of n items. n is even: median is the mean of the center pair of elements of the sorted list of n items.The smoothing calculation channel is the primary method of computing real-time medianvalues using the definition of median as given above. The smoothing output at a sampleposition is the median of the window of source channel samples including the currentsample and the previous samples in the window.The size of the window is 1 at the start of acquisition and increases incrementally untilthe final window size is reached. The median extraction method shifts between even andodd definitions as the window size is incremented.ScalingClick the Scaling button for access to options that allow you to modify the units orlinearly scale the output.Visit the online support center at www.biopac.com