Martin,
Thanks for the feedback.
It should be possible to increase the AM modulation depth, will look into this
Weird you can not set the modulation frequency below 1kHz. Kurt did some testing and he could use till at least 100Hz.
Not sure why the NFM deviation should increase with frequency. Could be PLL overshoot as I am modulating inside the PLL loop. If so there is not much I can do to improve.
The Bessel Nul technique is referred to in the tinySA? wiki measurement examples:?
You are most welcome if you want to provide some better text for the wiki.
