That is incorrect.
FM uses the frequency to transmit information so your Amp can be completely
saturated and still change freq. Phase mod is closely related to FM.
You might be thinking of QAM. Where you do have Phase and Amplitude
being used to send data.
Hy
i think u r confused!!!
simple way to understand :
modulating signal=input signal (signal to be sent)
for modulating signal,
use appropriate modulation technique to send data over any channel.
for more
study
carlson
frenzel
lathi (good for novice)
Regards
Hi,
Your statement is correct, that is, Whatever be the type of modulation, it is the amplitude of the modulating signal that is used to modulate the carrier.
Regards, Laktronics
since we need to transmit the message signal we use it to modulate the carrier, hence the name 'modulating signal'... to transmit the message signal we need to know its amplitude at each time instant at the receiver. so the amplitude of the message (modulating) signal will be used to change:
1. the amplitude of the carrier in case of amplitude modulation,
2. the frequency of the carrier in case of frequency modulation,
3. the phase of the carrier in case of phase modulation...
these figures explain the difference. the book of lathi will help you to understand the concept better.
if you have a signal a high frequency one, the you can send information of a slow frequency signal on within it,
if you vary the amplitude of the hf signal you have am, if you slightly modify the frequneyc i se less than 5% you have fm, and if you change its phase with respecto to a reference signal you have pm , see lathi for a mathematical covering, a lite one.
It is completely wrong. because only in AM amplitude will used for modulation. For FM and PM signals amplitude has a constant value and frequency and phase changes.