ad9954 fm
Is there any spur and interference with other channels ?(ch BW=25khz)
if yes,how to remove interference ?
You get some spurs of the modulation sampling frequency, that can't be filtered, cause you get a stepped frequency variation. It could be at best reduced by using Linear Sweep rather than Single-Tone Mode or increasing the sampling frequency.
how much sampling rate is enough?
Is there any other method for FM digital mod of voice?
I don't know. You can do a numerical simulation of the sampled voice signal and FM and determine the resulting spectrum.
In what softwares I can do the simulation?
I fm modulated a 1KHZ sound with 8khz deviation at ad9957 ,in that freq,I saw spurs at 3MHZ space relative to carrier and -60dbc.
this spur have no problem for me.what is your idea? is another problem?
I think, it should work this way.