Help with fourier transform for special square wave

[xanthium]

I know how to describe a square wave with Fourier analysis, but what if I'm looking for a square wave with "peaks" that are longer than the "valleys."
For example, from f(x)=1 {from 0 to 2}, f(x)=-1 {from 2 to 3}, f(x)=1 {from 3 to 5}, f(x)=-1 {from 5 to 6}... and so on in a periodic fashion.
Any ideas?
Thanks

 

[Andy Resnick]

That's not so bad- first, I'll rectify the wave and re-normalize it to make the functions easier to type.

Then, the wavetrain you describe is rect(x/2)*comb(x/4), where '*' is convolution. I'm pretty sure that will reproduce the function you describe. The Fourier transform is then Sinc(2q)*Sinc(4q), where sinc(x) = sin(x)/x, and q is the conjugate variable to x.

Tweak the original function as needed.