given a speech signal(.wav) file, we are required to plot cosine waves over it like cos(k1*x),cos(k2*x).I tried using dct function but to unable to proceedd

clc; clear;

syms m;

syms n;

[x, fs] = audioread('sample.wav');

x = x(:, 1);

xlen = length(x);

subplot(311)

plot(x)

subplot(312)

t=[-xlen:0.01:xlen];

plot(cos(2*pi*t/xlen));

y=dct(x);

y1=y*cos(2*pi/xlen);

y2=idct(y1);

subplot(313)

plot(y2) % i am required to plot cos waves around the .wav file but unable to proceed

Answer 1

[Chandra]

Hi,

By multiplying the cosine signal over the sound signal we can get the required signal

Use the following code to generate the plot

//Matlab code

>>[x, fs] = audioread('sample.wav');
>>t = linspace(0,length(x),length(x)); % or we can use t =0:length(x)-1;
>>n = x'.*cos(2*pi*fs*t);%multiplication is done using dot multiplication, the frequency value
                          %can be used depending on user values
>>plot(n);