What is Moving-average filter?
The simplest low-pass filter, which outputs the average of the latest N samples. It is y[n] = (x[n] + x[n − 1] + … + x[n − N + 1])/N, an FIR filter whose coefficients are all 1/N. Its DC gain is 1 and its gain is 0 at integer multiples of fs/N, so averaging over an interval that exactly matches the mains period, for example, removes noise at the mains frequency and its harmonics. Its coefficients are symmetric, so it has linear phase with a delay of (N − 1)/2 samples. Updating the sum by adding the newest sample and subtracting the oldest allows computation with few operations regardless of N.
Japanese name: 移動平均フィルタ
Moving-average filter appears in 1 practice question across 1 topic, including Digital Signal Processing Basics.