Analog Pulse Modulation Systems

Pulse modulation is a technique used in digital communication systems to convert analog signals into digital signals. It involves sampling the input analog signal and then quantizing and encoding the samples to generate a digital representation of the signal. There are several types of pulse modulation systems, but only one of them is analog, which is Pulse Width Modulation (PWM).

PWM (Pulse Width Modulation)

PWM is an analog pulse modulation technique that is commonly used in power control applications. It involves varying the width of the pulses in a train of periodic pulses to encode the analog signal. The width of each pulse is proportional to the instantaneous amplitude of the input analog signal. By controlling the duty cycle of the pulses, the average power delivered to a load can be controlled.

Advantages of PWM:

1. Efficient Power Transfer: PWM allows for efficient power transfer by controlling the average power delivered to a load.

2. Precise Control: PWM provides precise control over the average power delivered, allowing for accurate control of devices such as motors.

3. Low Power Losses: PWM minimizes power losses by reducing the time during which the power is dissipated.

Disadvantages of PWM:

1. Complexity: PWM requires complex circuitry to generate and decode the pulse train.

2. Higher Frequency Noise: PWM can introduce higher frequency noise due to the rapid switching of the pulses.

Conclusion:

Among the given options, only Pulse Width Modulation (PWM) is an analog pulse modulation system. PCM (Pulse Code Modulation) and Differential PCM are digital pulse modulation systems that quantize and encode the samples to generate a digital representation of the signal. Delta modulation is a digital pulse modulation system that quantizes the difference between consecutive samples. Therefore, the correct answer is option C, PWM.