What is frequency modulation ?

Explanation

### Step-by-Step Solution:

1. **Definition of Frequency Modulation**: Frequency modulation (FM) is a technique used in electronic communication, most commonly for transmitting information over radio waves. In FM, the frequency of a carrier wave is varied in accordance with the amplitude of the input signal (the modulating signal).

2. **Carrier Wave and Modulating Signal**: In frequency modulation, a high-frequency carrier wave is used to carry the information. The modulating signal is typically a low-frequency wave, which can be an audio signal or any other type of information signal.

3. **Amplitude and Frequency Changes**: In FM, while the amplitude of the carrier wave remains constant, the frequency of the carrier wave changes based on the instantaneous amplitude of the modulating signal. This means that the higher the amplitude of the modulating signal, the greater the frequency deviation of the carrier wave.

...