Audio Processing

Can someone tell me how to use low pass filter to limit the frequency of an audio signal to <6000hz? inorder to remove higher frequency components..

Answer 1

[Wayne King]

Hi Kathik, You have left out an important bit of information and that is the sampling frequency. I'll assume that is 44.1 kHz in this example.

In what follows, Hd1 is an FIR equiripple design and H2 is an IIR Butterworth design. I'll use 50 dB of attenuation.

d = fdesign.lowpass('Fp,Fst,Ap,Ast',6000,6200,0.5,50,44100);
Hd1 = design(d);
Hd2 = design(d,'butter');

To apply the filter to data, use

    output = filter(Hd1,input);

[PRIYANK SHAH]

Hi Wayne king and kartik,

can u suggest how to find out fft of the audio signal for 44.1 KHz sampling freq, before and after the same above low pass filter to check that ma filter is correct or not!!

Thank you.