Why is the number of filter coefficients required to be an odd number?
I calculated the order of the FIR filter to be 31 (N). so, the number of coefficients has to be 32 (N+1). so, I have to increase it to 33 to make it an odd number. Why the number of filter coefficients is required to be an odd number?
Why do you use symmetrical FIR filter with an odd length?
The effect of the filter on the rising and falling edges is exactly symmetrical. The plot on the right shows the same block pulse filtered with a low-pass single-pole IIR filter. The effect on both edges is quite different. Hence, for applications where the edges in the signal are important, this filter is often unsuitable. Figure 1.
Why are all frequencies delayed in the same way?
This means that all frequencies in the input signal are delayed in the same way, because the filter does not introduce phase distortion (also see The Phase Response of a Filter ). For example, if you use a FIR filter to change some characteristic of an audio signal, it will not also introduce a delay in some of the frequencies.
Why is the delay of FIR filter an integer?
If the number of taps is odd, then the delay of the filter is an integer number of samples, which is desirable for some applications. If you have an even number of taps, then you end up with a half-sample delay.
How are the coefficients of a FIR filter determined?
An FIR filter is designed by finding the coefficients and filter order that meet certain specifications, which can be in the time domain (e.g. a matched filter) and/or the frequency domain (most common). Matched filters perform a cross-correlation between the input signal and a known pulse shape.
How does a convolution of the FIR filter work?
In both cases, software performs a convolution between the coefficients and incoming data to indicate how well the coefficients overlap with the data in the time domain. To show how this process works, I’ll move to the frequency domain.