how pulse modulation takes place?i want the proper figure with explanation.
Pulse modulation is the process of transmitting signals in the form of pulses by using special techniques.
Pulse modulation is of three types:
1. Pulse Amplitude Modulation (PAM)
2. Pulse Width Modulation (PWM)
3. Pulse Position Modulation (PPM)
Pulse Amplitude Modulation (PAM)
The signal is sampled at regular intervals such that each sample is proportional to the amplitude of the signal at that sampling instant.
Pulse Width Modulation
The amplitude is maintained constant but the duration or width of each pulse is varied in accordance with instantaneous value of the analog signal.
Pulse Position Modulation
The sampled waveform has fixed amplitude and width whereas the position of each pulse is varied as per instantaneous value of the analog signal.
It is further modification of a PWM signal. It has positive thin pulses corresponding to the starting edge of a PWM pulse and negative thin pulses corresponding to the ending edge of a pulse.