i dont know ans. of this.
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.
Frequency Modulation and Phase Modulation
angle modulation is called non linear modulation because the information is stored in phase of the carrier signal
Phase modulation and frequency modulation are related because changes in the phase of a signal result in corresponding changes in its frequency. When the phase of a signal is modulated, it causes variations in the frequency of the signal as well. Therefore, in practice, it is difficult to separate phase modulation from frequency modulation, especially in communication systems where both aspects are interconnected.
The reason it is called exponential (non-linear) modulation is that the information is encoded within the phase of carrier.
The general name given to both Frequency Modulation (FM) and Phase Modulation (PM) is Angle Modulation. This term encompasses modulation techniques that vary the angle of a carrier wave to encode information, with FM varying the frequency and PM varying the phase of the wave. Both methods are widely used in communication systems for transmitting audio and data.
Frequency modulation Phase 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
Frequency modulation and Phase modulation
I think it is Frequency Modulation with Phase modulation which it the most bandwidth efficient
Advantages: it improves frequency stability. phase modulation n demodulation is easy as compared to frequency modulation.
Actually phase modulation was used for the color signal in all analog TV systems.Phase modulation, with some signal preprocessing, was used to indirectly get frequency modulation in many FM transmitters.Certain modems use phase amplitude modulation.etc.