how to determine a period for sinewave

i have been able to generate a sine wave now i want to find its period using matlab, how do i accomplish that?

Answer 1

[Azzi Abdelmalek]

Example

t=0:0.01:10;
y=sin(t);
[idx,idx]=findpeaks(y);
T=t(idx(2))-t(idx(1)) % The periode T (sec)

[2one]

practically this is unlikely to work (when noise is factored in)

Answer 2

[Wayne King]

You can use fft() as one way. Here's an example with a 100-Hz sine wave (sampled at 1 kHz).

   Fs = 1000; % sampling rate
    t = 0:1/Fs:1-1/Fs;
    x = cos(2*pi*100*t);
    xdft = fft(x);
    [maxval,idx] = max(abs(xdft));
    freq = (Fs*(idx-1))/length(x)

Therefore the period is 1/freq