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FIR filter

A filter whose output is a weighted sum of the last few inputs.

A finite impulse response filter computes y[n] = Σ h_i x[n - i] over L taps h_i; a single input spike affects exactly L outputs. A moving average is the FIR filter with all taps equal to 1/N.

Examples

  • A 5-tap low-pass with taps 1/8, 1/4, 1/4, 1/4, 1/8 in Q15 smooths the fan's 100 Hz accelerometer samples in a 32-bit accumulator.

  • A moving average of N readings is a FIR filter whose N taps are all 1/N.

See also

tap Q format fixed-point number
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