Channel width and Modulation (

Hi All,

I was wondering how the amount of “channel width” used can be
controlled and if it is determined by the kind of modulation being

For example, I used (using GMSK modulation) and transmitted
packets using board A and then captured the energy in the air using on board B. Attached figure shows the result of
the experiment.

I see that using GMSK occupies a channel width of around 5 Mhz
(2.418Ghz to 2.423Ghz) around the center frequency. Is this channel
width an independent parameter ? or is dependent on the modulation
(gmsk) ? I am interested in knowing how to “tune” this parameter.

I appreciate the help. Thanks much!