Re: GMSK bandwidth

On Wed, May 6, 2020 at 7:48 PM Artur Nogueira <artur.nogsj@gmail.com> wrote:

Hello guys,

I'm trying to generate a GMSK signal in accordance to the GSM specifications. To do so, I've been trying with both "GMSK Mod" and "GMSK Modulator" blocks, the last one with the following parameters:

To set these parameters, I considered (i) a sufficiently high base-band sampling rate (samples/symbol) in order to avoid aliasing; (ii) the well-known 0.3 BT product and (iii) a 156 bits GSM pulse, i.e. 1 time slot (I considered that GMSK provides 1 bit/symbol).

Nevertheless, my signals have a bandwidth which is much larger than the 200 kHz requirement.

What am I doing wrong? 

I think you want something more like 3 symbols for your pulse duration.  Not 156.

Brian