Discrete Fourier Transform function to avoid sampling errors

DFT function that takes an input signal of period N and sampling frequency fs.
The output is a vector that contains the module of its Fourier Transform. To do this, we have used the Matlab functions: fft and fftshift.
Also, in this function, we have restricted the signal period to be a multiple of 2 and greater than the sequence length. We have used the Matlab functions error and length to detect and throw errors in case this restrictions aren't met.
There is also a function to create a sine signal which can be used as an input in the DFT function.

MORE INFO AND EXAMPLES: http://www.behindthesciences.com/signal-processing/fouriertransformmatlabtutorial