Question

Hi,
I have this task about convolution and I need to write it as a code in matlab.

I have input signal x[n]=0.3 ∗ sin(n/5) + sin(n/50) :

a) Create your own delta signal h[m] that removes the higher frequency sinusoidal component to get yl[n].

b) Subtract the yl[n] from the original signal(x[n]) and get the higher frequency component yh[n] (pay attention to array sizes and phase shift) .

c) Plot x[n], yl[n] and yh[n] on the same graph

Answer 1

%% PART 1

n=-1000:1:1000; %% time defined

wc=1/50; %% cutoff freqeuncy

h=(wc/pi)*sinc(wc*n); %% filter defined

x=0.3*sin(n/5)+sin(n/50); %%input signal

yl=conv(x,h); %%convolution

p=length(x);

q=length(h);

n1=-(p+q)/2+1:1:(p+q)/2-1; %% TIME DEFINED

x1=0.3*sin(n1/5)+sin(n1/50);

%% PART 2

yh=x1-yl; %%HIGH FREQUENCY DEFINED

%% PART 3

%% MULTIPLE GRAPH PLOTTED AT SAME TIME

hold on

plot(n1,yl,'r')

plot(n1,yh,'o')

plot(n1,x1)

hold off

ylabel('amplitude');

xlabel('time');