QAM is a combination of phase modulation & amplitude modulation.
the maximum amplitude of carrier wave varied with respect to instantaneous values of message signal is called amplitude modulation
AM imply amplitude modulation of a carrier signal
because noise usually changes the amplitude not frequency.
Pulse-Amplitude Modulation
a rectifier and low pass filter
AM is amplitude modulation. AM detection is the process of demodulation or recovering the information encoded in the signal through amplitude modulation. AM detection can be done through a simple diode detector which rectifies the AM signal.
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.
AM - Amplitude Modulation FM - Frequency Modulation
QAM is a combination of phase modulation & amplitude modulation.
In amplitude modulation, modulation depth refers to the ratio of the unmodulated carrier amplitude to the amplitude deviation for which the modulated carrier wave reaches its minimum value. If this minimum value is zero, the modulation depth is 100%.For amplitude modulation,modulation depth = (a-b)/(a+b),wherea is the unmodulated carrier amplitude, andb is the minimum amplitude deviation.The modulation depth ratio is also referred to as the modulation index.
amplitude modulation is where we modulate our signal with a carrier signal amplitude changes but frequency remains constant in amplitude modulation
Frequency modulation have some advantages over amplitude modulation, FM is not sensitive to the amplitude noise, and have high efficient use of transmitted power
Normal frequency range for amplitude modulation is 550kHz to 1610kHz
In amplitude modulation, modulation depth refers to the ratio of the unmodulated carrier amplitude to the amplitude deviation for which the modulated carrier wave reaches its minimum value. If this minimum value is zero, the modulation depth is 100%.For amplitude modulation,modulation depth = (a-b)/(a+b),wherea is the unmodulated carrier amplitude, andb is the minimum amplitude deviation.The modulation depth ratio is also referred to as the modulation index.
Amplitude modulation is a method of sending information by modifying the intensity of a carrier wave.
the maximum amplitude of carrier wave varied with respect to instantaneous values of message signal is called amplitude modulation