FirstOrderFilter

The First Order Filter transform applies a First Order Filter to the input (In) signal. This is useful for purposes such as noise reduction. The Time Constant is specified in the transform's properties in seconds.

When the Reset port receives a non-zero transition, the Out signal is set to the value of the In signal.

You can adjust the cut-off frequency of the filter by changing the Transform's Time Constant property.

FOF-properties-marked

The Transform uses this algorithm to calculate output transitions:

Filter Algorithm

The Time Constant, represented by the Greek letter tau(tau) , is used in this formula to calculate the cut-off frequency: formula-cutoff-frequency
If the default Time Constant of 1 is used, the cut-off frequency is approximately 0.16 Hz.

For more information, see https://en.wikipedia.org/wiki/Low-pass_filter#Continuous-time_low-pass_filters

The figure below shows an example of a First Order Filter being used to remove high-frequency noise from a sine wave signal. The input sine wave and the "noise" are generated by a C# Snippet Signal Generator.

FOF-SineWave

Related Topic:

Signal Processing Transforms