In a communication system, what is meant by modulation? State any two types of modulation.

Explanation

### Step-by-Step Solution:

1. **Definition of Modulation**:
Modulation is the process of superimposing a low-frequency signal (also known as the modulating signal) onto a high-frequency wave (known as the carrier wave). This allows the transmission of information over long distances by varying certain properties of the carrier wave.

2. **Understanding the Components**:
- **Low-Frequency Signal**: This is the signal that contains the information we want to transmit. It is often referred to as the modulating signal.
- **High-Frequency Wave**: This is the carrier wave that carries the information through the communication medium.
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