Constraints on number of taps in a FIR filter vs. FFT length

1. How does the number of taps affect the frequency response of your FIR filters?
2. How do I choose the number of taps for my FIR filter?
3. What is FIR filter length?

How does the number of taps affect the frequency response of your FIR filters?

An FIR's tap is simply a coefficient value and the impulse response of an FIR filter is the filter's coefficients. The number of taps (N) is the amount of the memory needed to implement the filter. More taps mean higher frequency resolution, which in turn means narrower filters and/or steeper roll‐offs.

How do I choose the number of taps for my FIR filter?

The number of FIR taps, (often designated as “N”) is an indication of 1) the amount of memory required to implement the filter, 2) the number of calculations required, and 3) the amount of “filtering” the filter can do; in effect, more taps means more stopband attenuation, less ripple, narrower filters, etc.

What is FIR filter length?

The impulse response is the time reverse of the minimum-phase impulse response and so the bulk delay through the filter is approximately the length of the filter; 42.7 ms.