The definition is that the 96.3 is the frequency that you are transmitting when no other signal information is included in the carrier wave. As soon as you add frequency modulation, the carrier frequency starts changing back and forth around the center frequency.
The maximum allowed frequency deviation in the FM broadcast band is +/_ 75 Khz. 150 Khz total. The actual amount at any instant depends on the frequency of the audio at that instant. It is far less than 75 Khz, The actual audio bandwidth is about 15 Khz.
The maximum allowed frequency deviation in the FM broadcast band is +/_ 75 Khz. 150 Khz total. The actual amount at any instant depends on the frequency of the audio at that instant
That's not quite correct. The amount of frequency deviation depends upon the modulating frequency amplitude (loudness), not it's frequency. How fast the deviation occurs is determined by the modulating frequency.
Maybe the OP doesn't understand how little the frequency changes with FM modulation.
When modulated as loud as possible, the frequency changes from 93.525MHz to 93.675MHz. Most of the time the frequency deviation is much less, maybe from 93.59MHz to 93.61MHz.