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.
QAM is a combination of phase modulation & amplitude modulation.
Frequency modulation Phase modulation
initially the two beams i.e. one reflected and one transmitted from semi reflecting glass were in different phase but when they superimpose two interference take place - constructive and destructive. since in both the interferences amplitude changes.
Frequency modulation and Phase modulation
by maximizing the measurable differences between shifts in phase and amplitude
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.
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.
An analog or digital modulator can perform amplitude, frequency, and phase modulation. These modulators are commonly used in communication systems to modulate a carrier signal in order to transmit information.
amplitude modulation is used
IF we use frequency modulation for transmitting video signal this can cause phase shifting .and eyes can percieve this distortion effect easly . and requires more bandwidth to send the signal .Color levels are adjusted by amplitude in TV .So it s more logic to use Amplitude modulation .
Amplitude Frequency
to maintain the constant frequency and the phase parameters at the output