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Removing Bias from Signals

Overview​

Removing bias from a signal accounts for any DC offset present within the signal, causing an offset from zero (SAE J1727 3.3)

  • Averaging data over a defined time range where metric values are at a constant known value, time range selected prior to the event (i.e. pre-trigger data), can be used to correct any signal bias (SAE J1727 3.3.1)

Required Inputs​

  • Time History Signal
  • Desired offset for x values and y values (if applicable)

Calculation​

  1. Add selected offset values to both the x and y values
  2. If offset values are not specified, the average value of the first 500 samples before the tigger point is subtracted from the entire signal

Removing Bias Example​

Before removing bias

Before bias is removed from signal

After removing bias

After offset of -0.2 is applied to x values and offest of -10 is applied to y values to recenter signal around y = 0