problem about filter order in design tool

this is the filter i designed

the specify order is 101 , and in current filter information the order is 100 , is there any problem about the order , i have no idea .

Answer 1

[Star Strider]

There is no problem. The filter order the MATLAB routines design is determined by the filter requirements you set, according to some fairly standard algorithms that are probably in most signal processing textbooks.

I would also experiment with the ‘Minimum Order’ option to see if you can get the same passband and stability with a shorter filter.

Answer 2

[Honglei Chen]

The reason for this discrepancy is because Hann window has a trailing zero at the end. And I believe in the info window, it didn't count that zero since you don't really need it.

[Roger]

really thanks