EMA (exponential moving average)

EMA (exponential moving average)

IIR (Infinite Impulse Response) filters, such as EMA (exponential moving average), have nonlinear phase, resulting in different amounts of delay for different frequency components in the smoothed waveform. On the other hand, Ella
(Finite impulse response) filters, such as SMA (Simple Moving Average), produce the same delay for all frequency components in the smoothed waveform. For an "N" length fir filter the amount of lag is (N - 1) / 2. For example, three-bar SMA will have a delay of exactly one bar for all components in its frequency smoothed out and two bar SMA will be a delay of only one half of one bar. So what value of N (order of filter) should we choose? Clearly, we want to minimize the order of the fir filter to reduce the lag.