On Mon, Jun 26, 2017 at 1:50 PM Brashendeavours <
address@hidden> wrote:
Thank you, Kevin. That is reassuring.
My next question then, is since the deviation is affected by both amplitude and frequency, how would you recommend I empirically determine/set a peak deviation of 2400Hz for 1200Hz baseband?
Is this experiment not possible to visualize/determine on a waterfall, simply?
I think your confusion may be that deviation != occupied bandwidth.
If the sensitivity on the FM mod block is (2*pi*2400)/(48000), and the sample rate is 48k, then the maximum deviation is 2.4kHz provided the baseband signal does not exceed +/- 1. You can verify this by making the baseband input a very low frequency sine wave, say 0.1 Hz. Viewed in the waterfall you should then see the carrier move between -2.4 and +2.4kHz.
To determine the bandwidth occupied by the FM signal, you can use the Carson bandwdith rule, which says the bandwidth required is the peak deviation _plus the highest baseband frequency_, times two.