Hi Prisma,
The initial figures may be getting unintentionally updated because the plot and stem functions in the code rely on gcf (which returns the current figure handle) to display the data. As a result, even after the correct values are plotted initially, the figures might change later in the run. This can occur for various reasons, one common cause is manually selecting a figure by clicking on it, which makes it the current figure and redirects subsequent plots to it.
To avoid such issues, it's advisable to define the figures and axes explicitly for each graph. A basic example of the syntax would be:
figN=figure(N)
axN=axes('parent',figN);
stem(axN,_,_);
plot(axN,_,_);
Please also find the implemented code with the correct desired figures:
clear
clc
N = 1024;
dt = 2/(N-1);
t = 0:dt:2;
ft = zeros(1,length(t));
ft(1:N/2-1)= 2;
ft(N/2:end)= -2;
%% defining the figure and the axes explicitly
fig1=figure(1);
ax1=axes('parent',fig1);
plot(ax1,t,ft,LineWidth=2) %plotting to the specific axes
title("Original Plot f(t) v/s t")
xlabel("t")
ylabel("f(t)")
grid
xlim([t(1)-1,t(end)+1])
%Finding fourier series using the below function
FourierSeries_Calculator(ft,t,dt,100);
function FourierSeries_Calculator(ft,t,dt,n)
arguments
ft (1,:) double
t (1,:) double
dt (1,1)
n (1,1) {mustBeNumeric,mustBePositive,mustBeGreaterThan(n,20)}
end
T0 = t(end)-t(1);
w0 = 2*pi/T0;
[a,w,phase] = deal(zeros(1,2*n+1));
for m = -n:n
a(m+n+1) = sum(ft.*exp(-1i*m*w0.*t))*dt/T0;
w(m+n+1) = m*w0;
phase(m+n+1) = angle(a(m+n+1));
end
fig2=figure(2);
ax2=axes('parent',fig2);
stem(ax2,w,abs(a))
title("Magnitude Spectrum")
xlabel("w0")
ylabel("|a_n|")
grid
fig3=figure(3);
ax3=axes('parent',fig3);
stem(ax3,w,phase)
title("Phase Spectrum")
xlabel("w_0")
ylabel("Phase (in radians)")
grid
FourierSeries_Plot(a,t,w0,n);
end
function FourierSeries_Plot(a,t,w0,n)
arguments
a (1,:)
t (1,:)
w0 (1,1) {mustBePositive}
n (1,1) {mustBePositive}
end
FourierS = 0;
%% defining the figure and the axes explicitly
fig4=figure(4);
ax4=axes('parent',fig4);
for m = -n:n
FourierS = FourierS + a(n+m+1)*(exp(1i*w0*m.*t));
plot(ax4,t,real(FourierS),LineWidth=2) %plotting to the specific axes
pause(0.01)
end
clf(fig4)
fig4=figure(4);
ax4=axes('parent',fig4);
plot(ax4,t,real(FourierS),LineWidth=2)
title("Fourier Series Representation")
xlabel("t")
grid
end
%OUTPUT
Using clf without an argument clears the current figure, which may not be the intended one. To avoid this, it’s recommended to pass the specific figure handle to clf.
Hope this helps.
