Trying to plot a sine wave, getting a straight line.

I need to create a time series using x(n)=sin(2pi/N)*n where N=256 and plot the amplitude. I keep getting a straight line instead of a sine wave. Any pointers?

    %Create time series x(n)
N=256;
x=zeros(N,1); %allocate space
for n=1:N;
    x(n)=sin((2*pi)/N)*n;
end 
%Plot x(n)
figure(1)
n=0:255;
plot(n,x(1:N))
xlim([0 255])
ylim([-120 120])
xlabel('n')
ylabel('Amplitude')
title('x(n)'

Answer 1

[Roger Stafford]

You have placed your ’n’ variable outside the parentheses for the sine function. That would make it a straight line. It should be this to get a sine curve:

   x(n)=sin(2*pi/N*n);

[Nat]

Thanks Roger, that worked!