modulation index

[contau]

how are the modulation index in broadcast FM and AM. Someone tell me pls?

 

[Hero999]

Modulation index - Wikipedia, the free encyclopedia

 

[contau]

what values is regualar used in pratical?

 

[crutschow]

In the USA, I believe the maximum commercial AM radio modulation index is 1 (100%) and the maximum commercial FM radio modulation index is 5.

 

[Hero999]

In practise the modulation isn't constant but varies depending on the signal being transmitted.

With AM, the maximum index is 1, beyond that distortion occurs.

With FM the maximum index is limited by the bandwidth which is theoretically infinite but reduced to an acceptable level for practical reasons.

 

[contau]

i have simulated FM detector using NI multisim, but when i used oscilloscope to see final signal. i had two different result:
+when no using spectrum analyzer.
+using spectrum analyzer.
can anyone pls explain this difference?