One disadvantage of the standard amplitude modulation system is that 67% of the power is used for the carrier, but the carrier transmits no information, so it can be considered as wasted power.The 34% remaining power is split between two mirror opposite sidebands so, in effect, you really only have 17% of your power used to carry the signal.
the modulation system is of FM
Frequency modulation Phase modulation
QAM is a combination of phase modulation & amplitude modulation.
whatbis GMSK MODULATION ?
The difference between frequency modulation and phase modulation is that with frequency modulation the angular frequency of the signal is modified while with the phase modulation, the phase angle of the signal is modified.
It is called angle modulation because it changes the angle of the carrier which is exponential, e.g. sin theta = {(e*j theta + e (-j theta)} / 2
One disadvantage of the standard amplitude modulation system is that 67% of the power is used for the carrier, but the carrier transmits no information, so it can be considered as wasted power.The 34% remaining power is split between two mirror opposite sidebands so, in effect, you really only have 17% of your power used to carry the signal.
AM - Amplitude Modulation FM - Frequency Modulation
Advantage - 1. Phase modulation & demodulation is easy compared to Frequency modulation. 2. Phase modulator is used in determining velocity of moving target by extracting Doppler information. Doppler information needs stable carrier which is possible in phase modulation but not in frequency modulation. Disadvantage - 1. Phase ambiguity comes if we exceed its modulation index pi radian(180 degree). 2. we need frequency multiplier to increase phase modulation index. Visit my website http://harshit.org
modulation
Frequency Modulation and Phase Modulation
frequency modulation..
due to velocity modulation density modulation occurs in TWT
the modulation system is of FM
i dont know ans. of this.
Frequency modulation Phase modulation