In case of FIR filter design, is the following relation always applicable or there are other relations/formulas also?

If window length is denoted by $M$ ,then filter order will be $M-1$


Yes. The number of taps or coefficients in a FIR filter (or window length as you call it) tell the order of the filter. A more general way to see it, to avoid confusions, is to think of the order as the largest delay in the filter. For example, consider the following naive reverb:

$$y[n] = a x[n] + (1 - a) x[n-D]$$

Even though there are only two (visible) coefficients, the order of the filter is $D$ because it’s the largest delay. The window length is $D+1$ but all the middle coefficients are $0$, hence not visible.

| improve this answer | |
  • 1
    $\begingroup$ calling a single delay tap (plus an undelayed tap) a "reverb" is a bit of a stretch. $\endgroup$ – robert bristow-johnson Jul 18 at 23:54
  • $\begingroup$ Yeah, you’re right. I hope the “naive” makes it a bit more appropriate. $\endgroup$ – Michael Gruner Jul 19 at 0:56
  • $\begingroup$ Is a zero coefficient a "tap"? $\endgroup$ – Cedron Dawg Jul 19 at 23:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.