Of the following which is preferred modulation scheme for digital communication.

Options

A. PCM
B. PAM
C. PPM
D. PTM

Explanation

To determine the preferred modulation scheme for digital communication from the given options, we can follow these steps:

### Step 1: Understand the Options
The options provided are:
1. PCM (Pulse Code Modulation)
2. PAM (Pulse Amplitude Modulation)
3. PPM (Pulse Position Modulation)
4. PTM (Pulse Time Modulation)

### Step 2: Define Each Modulation Scheme
- **PCM (Pulse Code Modulation)**: This is a method used to digitally represent analog signals. It involves sampling the signal and quantizing the amplitude of the samples to a series of coded pulses. PCM is widely used in digital communication systems because it provides high fidelity and is robust against noise.

- **PAM (Pulse Amplitude Modulation)**: This technique conveys information by varying the amplitude of the pulses. While it is used in some digital applications, it is more susceptible to noise and distortion compared to PCM.

- **PPM (Pulse Position Modulation)**: In this scheme, information is encoded in the position of the pulse within a given time frame. Although it can be efficient in certain applications, it is not as commonly used for general digital communication.

- **PTM (Pulse Time Modulation)**: This method modulates the time duration of pulses to convey information. It is less popular and not typically used in standard digital communication systems.

### Step 3: Identify the Preferred Modulation Scheme
Among these options, **PCM (Pulse Code Modulation)** is the most preferred modulation scheme for digital communication due to its robustness and effectiveness in accurately transmitting digital signals.

### Conclusion
The preferred modulation scheme for digital communication from the options provided is **PCM (Pulse Code Modulation)**.

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