With FM modulation the zero span graph does not show the modulation but a simple trick can help.
When you look at the close in spectrum of a FM signal using a wide but steep RBW the signal looks like this.
The top of the filters is more or less constant but the slopes show signs of changing frequencies.
By positioning the zero span precisely at the slope of the filter the modulation becomes visible
The wide FM modulation of the tinySA is indeed also a sawtooth with a somewhat higher frequency as the AM modulation.
