“Symbol Rate: ...............................might influence the bandwidth?”
To achieve a bandwidth of 600 Hz, setting the bit rate to 600 bps would work ideally. However, there are several practical considerations and factors that might influence the actual bandwidth required. To account for these factors, you might choose a bit rate slightly lower than the desired bandwidth if you plan to use filtering with a non-zero roll-off factor.
“Sample Time and Stop Time:………….. Is this a correct configuration?”
Ideally, this would be the correct configuration to obtain a signal of bandwidth of 600 Hz, when the frame length is 1, i.e., passing one bit at a time. However, from your model, I can see that you are passing vector inputs to the DPBSK modulator. In the official MATLAB documentation at https://in.mathworks.com/help/dsp/ug/sample-and-frame-based-concepts.html#bso3re7, it is given that when passing vector inputs, the modulator blocks consider each vector input as one frame. In this situation, the sample time must be the time length of each frame = 
. In this case, it would be 
. To run a simulation where only one frame is transmitted, then the stop time must also be set to the time length of each frame, which in this case would be approximately 0.347 seconds as you have calculated.
. In this case, it would be . To run a simulation where only one frame is transmitted, then the stop time must also be set to the time length of each frame, which in this case would be approximately 0.347 seconds as you have calculated.“Spectrum Analyzer Placement……… visualize the generated signal's frequency spectrum?”
The “Spectrum Analyzer” block displays the frequency spectrum of any signal that is provided at its input. In your model, the “Spectrum Analyzer” block is placed in the right location to obtain the frequency spectrum of the filtered signal.
Hope this helps!
