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.
amplitude modulation is used
what is phase modulation changing of the phase depending upon the modulated signal is said to be a phase modulation
Frequency modulation Phase modulation
QAM is a combination of phase modulation & amplitude modulation.
For phase opposition disposition (POD) modulation all carrier waveforms above zero reference are in phase and are 180 out of phase with those below zero.
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.
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
amplitude modulation is used
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.
what is phase modulation changing of the phase depending upon the modulated signal is said to be a phase modulation
i dont know ans. of this.
QAM is a combination of phase modulation & amplitude modulation.
Frequency modulation Phase modulation
A phase-locked loop (PLL) can be used as a universal detector for Amplitude Modulation (AM) by utilizing its ability to track the phase and frequency of the incoming modulated signal. The PLL locks onto the carrier frequency of the AM signal, allowing it to demodulate the envelope variations caused by the modulation. By comparing the output of the PLL with the original carrier frequency, the modulation information can be extracted as the difference between the two signals. This makes the PLL an effective detector for demodulating AM signals across a wide range of frequencies and modulation depths.
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
For phase opposition disposition (POD) modulation all carrier waveforms above zero reference are in phase and are 180 out of phase with those below zero.