What is PAM, PWM and PPM?

Hint: Pulse modulation is a type of modulation in which the signal is sending in pulses. It can be used to transfer analog data. Continuous signals sampled at regular intervals in pulse modulation.
Pulse modulation divided into two types:
Analog: The sample amplitude indication is indefinitely changeable.
Digital: Indicates the amplitude of a sample at the nearest preset level.

Complete answer:
PAM is an abbreviation for Pulse Amplitude Modulation.
PWM is an abbreviation for Pulse Width Modulation.
PPM is an abbreviation for Pulse Position Modulation.
These are the types of pulse modulation.
Pulse Amplitude Modulation (PAM):
It is the most basic type of Pulse Modulation. Each sample in this sort of modulation is proportional to the amplitude of the signal at the time of sampling. As the signal traces out the path of the entire wave, the PAM signal follows the amplitude of the original signal. In this case, a Nyquist-sampled signal can be reconstructed by passing it through an efficient Low Pass Filter (LPF) with a precise cutoff frequency. PAM is simple to create and demodulate. This method sends data by encoding it in the amplitude of a series of signal pulses.
Pulse Width Modulation (PWM):
Pulse Width Modulation (PWM), also known as Pulse Duration Modulation (PDM), or Pulse Time Modulation (PTM), is an analog modulation system in which the duration, width, or time of the pulse carrier varies proportionally to the instantaneous amplitude of the message signal. The width of the pulse varies in this manner, but the signal amplitude remains constant. Amplitude limiters are used to keep the signal's amplitude consistent. These circuits limit the noise by clipping the amplitude to the desired level.
Pulse Position Modulation (PPM):
The amplitude and width of the pulse are both kept constant in this sort of modulation. We alter the position of each pulse about a specific pulse. In this case, a single pulse with the required number of phase changes is sent. So, pulse position modulation is an analog modulation system in which the amplitude and breadth of the pulse remain constant while the position of the pulse concerning the direction of a reference pulse varies depending on the instantaneous value of the message signal.

Note:
Applications of PAM:
1. It is mostly used in Ethernet communication.
2. This approach is used by many microcontrollers to create control signals.
3. It is employed in photobiology.
4. It functions as a driver for LED circuits.

Applications of PPM:
1. It is utilized in air traffic control and telecommunications networks.
2. Pulse code modulation is used in remote-operated autos, planes, and trains.
3. It is used to compress data and, therefore, for storage.

Applications of PWM:
1. Drive a buzzer with varying levels of volume.
2. Control the motor's speed.
3. Control the movement of a servo.
4. Make an analog output available.
5. Create an audio signal.
6. Message encoding in telecommunications.