What does this spectrum of FSK mean?

Hello all,
in the figure shown, a spectrum of an FSK signal ,

What i want to know, where's the contribution of bit rate on spectrum?

in other words, will it shrink or extended when bit rate increased/decreasd?

Thanks,
Ahmad,

The two main peaks are the frequency shift. The spacing between the minor peaks are due to the data bit rate. As the bit rate increases the small peaks will move further apart and the ones outside the two main peaks will become larger.

Sorry, Does this mean that increasing bit rate will decrease BW? I didn't understand it well..

The bandwidth can never be less than the frequency shift. It is usually the sum of the frequency shift and the bit rate.