high grade butterworth bandpass filter

hello, I want to design a high grade butterworth bandpass filter. however, the frequency range is low (10-35 hz).the filtered signal is not plotted.

code: butter(10,[10 35]/1000) %10th-order butterworth bandpass filter

why not plotted signal? matlab does not fail.

Answer 1

[Star Strider]

Assign outputs:

[z,p,k] = butter(10,[10 35]/1000);   %10th-order butterworth bandpass filter

then use zp2sos and use second-order-section representation of the filter.

For the Bode plot, he freqz function is your friend, here!

Otherwise use the filtfilt function to do the actual filtering.

To plot anything, use the plot function.