frequncy modulation

[prad]

hi in fm the frequency of the wave is continiously changing then how is
fm frequency measured ?
is it the frequency of the carrier wave ?

 

[Phil Allison]

"prad"

hi in fm the frequency of the wave is continiously changing then how is
fm frequency measured ?
is it the frequency of the carrier wave ?

** A surprisingly simple and insightful question.

The "frequency" of an FM modulated wave = the *average frequency* !!!

There is a fixed carrier frequency that becomes apparent when there is NO
modulation - ie silence in a broadcast program. FM modulation shifts this
BASE frequency UP & DOWN about the centre frequency.

When averaged over a reasonable time interval ( say one second) the average
frequency is the same as the BASE frequency.




........ Phil

 

[Hans Lohninger]

More on frequency modulation can be found here (classical radio FM):

http://www.vias.org/basicradio/basic_radio_34_01.html

and here (for digital signals):

http://www.vias.org/feee/commun_05.html

Regards,

Hans