he output is the change in the input over the most recent sampling interval h. The effect of this filter is similar to that of an analog differentiator circuit . 5. Two-term average filter: The output is the average (arithmetic mean) of the current and previous input: This isa simple type of low pass filter as it tends to smooth out high-frequency variations ina signal. (We will look at more effective low pass filter designs later). 6. Three-term average filter: This is similar to the previous example, with the average being taken of the current and two previous inputs: As before, x -1 and x -2 are taken to be zero. 7. Central difference filter: This is similar in its effect to example (4). The output is equal to half the change in the input signal over the previous two sampling intervals:
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