New to DSP. fvtool output different to parameters of filter exported from filter designer

Hi,

Im probably missing something obvious here. I've created a LPF using the filter designer as pictured and run the following code;

fvtool(HdL)

fvtool(HdL,'Analysis','impulse')

fvtool(HdL,'Analysis','freq')

Could anyone please explain the difference between the fvtool output and the filter designed and/or what I've done wrong?

Many Thanks

Answer 1

[Nipun Katyal]

Hi,

In order to visualize the frequency range for your filter you need to set the sampling frequency, otherwise it will use the default value of sampling frequency for fvtool, You can change the sampling frequency under the Analysis menu. In the drop down menu you will find Sampling frequency at the bottom. The defualt value is 1, you can change it to 48000 in your case and the frequency will be adjusted accordingly.