fsk

Hello, I am wondering how to superimpose a square wave input signal onto a fm carrier signal?

I am trying to derive an equation for an FSK signal in the time domain - see FSKTime I then want to use Fourier analysis/transforms to find an equation so that I can plot the frequency response - see FSKFreq I think I am nearly there, but the 2 delta terms and the minus signs in the FSKFreq...