about freqs_m function

[N,Wn]=buttord(8000*pi,32000*pi,1.421,22.380,'s')

[B,A]=butter(N,Wn,'s')

freqs(B,A)

[db,mag,pha,w]= freqs_m(B,A,36000*pi);

subplot(2,1,1);

plot(w/(2000*pi),db);

xlabel('frequency in KHZ');

ylabel('Magnitude in db')

grid on;

subplot(2,1,2);

plot(w/(2000*pi),pha);

xlabel('frequency in KHZ');

ylabel('phase in radians/s'); grid on;

% error message

Undefined function or variable 'freqs_m'. Error in hw1p6 (line 7) [db,mag,pha,w]= freqs_m(B,A,36000*pi); >>

Answer 1

[Star Strider]

You have to download freqs_m (link) from Code Forge.

Answer 2

[Jan]

The message is clear: The folders of the Matlab path do not contain this file. Most likely you want to download it at first, e.g. from FEX: digital-signal-processing-using-matlab . Then add the folder, which contains this function to the path:

addpath(FolderName, '-end')

To store the modified path permanently, use

savepath

Both can be done by a GUI also:

pathtool

Answer 3

[ahmed allaheani]

thank you very much guys. the code is working perfectly