Question

MATLAB. Design your own low-pass shelving filter which can boost the low frequency of given music signal. After designing filter, apply the filter to the original music signal and observe the result. Include following plots.
A. Magnitude and phase plot of your filter.
B. Magnitude plot of original signal
C. Magnitude plot of filtered signal

Answer 1

MATLAB CODE

close all,
clear all,
clc,

ProjectPath = pwd;
MusicSignal_ = strcat(ProjectPath,'\Sample.wav');

[x, Fs, nbits] = wavread(MusicSignal_);
subplot(1,2,1); plot(x);
title('Original Music Signal Magnitude Plot');
%soundsc(y,Fs);

grid on,
Fc=200; %Cut off Freq in Hz
Order=2;

Wn = Fc/(Fs/2);
b = fir1(Order,Wn,'low'); hd = dfilt.dffir(b);
y = filter(hd,x);
subplot(1,2,2); plot(y); grid on, ylim([-3,3]);
str = strcat('Filtered InputSignal, Fc = ',num2str(Fc),' Hz'); title(str);
figure,
freqz(b,1,512);

0 -1 -2 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Normalized Frequency (x rad/sample) 0 -50 -100 -150 -200 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Normalized Frequency xI rad/sample) Phase (degrees) Magnitude (dB)

Original Music Signal Magnitude Plot Filtered InputSignal, Fc 200 Hz 0. 03 0.2 0.1 . .. -01 0.2H -0.3 U.4 12 14 10 13 x 10 10