Removing DC Bias

Normalize to greatest ½ second activity during 5 second trial. A window of twenty-five .02 second intervals of integrated EMG is moved one interval at a time across the 5 seconds of data to find the greatest EMG. The average integrated EMG during the ½ second is used to compute the normalization factor.

This is just an example, so the user should modify the meta-command to suit their own needs.

The task is as follows:

• Compute a normalization factor
• Normalize to greatest ½ second during 5 second trial.
  

This is accomplished by using an average filter (see the bottom of the page)

• A window of twenty-five .02 second intervals of integrated EMG is moved one interval at a time across the 5 seconds of data to find the greatest EMG.
• The average integrated EMG during the ½ second is used to compute the normalization factor.

The following are examples of how to do the above task. The maximum value is calculated is a little different in the following examples. You should choose the method which makes the most sense to you.

1. Process EMG
   1. High pass filter (remove DC offset)
   2. Calculate RMS of predetermined time intervals (example: 0.02 seconds)
2. Normalize
   1. Calculate the average of the processed signal over 30 second intervals
   2. Get the maximum of the 30 second interval
   3. Normalize by dividing the average by the maximum

You can download the sample files here.

The download contains:

• MVC_Example.cmz with -
  • 3 MVC trial
  • 2 Dynamic Trials
• EMG_Norm_MVC_Max_Mean_Example_1.v3s (Example Pipeline Script)
• EMG_Norm_MVC_Max_Mean_Example_1.v3m (Example Meta-Command)
• Call_EMG_Norm_MVC_Max_Mean_Example_1_Meta.v3s (Example Pipeline Script calling Meta-Command)

1. Process EMG
   1. High pass filter (remove DC offset)
   2. Calculate RMS of predetermined time intervals (example: 0.02 seconds)
2. Normalize
   1. Calculate the average of the processed signal over some time interval (in this example: 0.5 seconds)
   2. Get the maximum of the processed signal
   3. Calculate the maximum of the average signal
   4. Normalize by dividing the processed signal by the maximum average over the interval

You can download the sample files here.

The download contains:

• MVC_Example.cmz with -
  • 3 MVC trial
  • 2 Dynamic Trials
• EMG_Norm_MVC_Max_Mean_Example_1.v3s (Example Pipeline Script)
• EMG_Norm_MVC_Max_Mean_Example_1.v3m (Example Meta-Command)
• Call_EMG_Norm_MVC_Max_Mean_Example_1_Meta.v3s (Example Pipeline Script calling Meta-Command)