In A.M signal, does carrier power is dependent on modulation index?

[nitin.maurya1]

In A.M signal, does carrier power is dependent on modulation index?

 

[albbg]

An AM modulated signal can be represented as:

s(t) = A*[1 + k*cos(ωm*t)]*cos(ωc*t)

where k is the modulation index, ωc the carrier frequency and ωm the modulant frequency.

Developing the math we will have:

s(t) = A*k/2*[cos(ωc-ωm) + cos(ωc+ωm)] + A*cos(ωc*t)

then the amplitude of the carrier is independant from the modulation index, while the two sidebands will depend from both k and A

 

[ark5230]

Just try two different modulation index signals. The RMS value will tell you about the power that it does change.

 

[fisher101]

modulation index depends on two things 1 amplitude of carrier and 2 amplutude of base band so without any trouble you can say that the power does depend on the modulation index the greater the modulation index the les the carrier power

 

[albbg]

Just try two different modulation index signals. The RMS value will tell you about the power that it does change.

Measuring the power of the modulated signal you will take into account both carrier + sidebands power unless you filter out the two sidebands

 

[KerimF]

In A.M signal, does carrier power is dependent on modulation index?

No, it doesn't.
But increasing the modulation index increases the power of the AM signal (carrier + two sidebands).

Kerim

Practically, the transmitter ouput has a maximum power. So, in order not to exceed this maximum, the carrier power should be reduced when higher modulation index is needed.