Modulation

- Modulation is the addition of information to an electromagnetic or optical signal carrier.

- It is the process of varying one more properties of a carrier signal(high frequency signal) with a modulating signal that typically contains information to be transmitted.

Purpose

- To generate a modulated signal suited to the charecteristics of a transmission channel.

- To transfer the message into the available high frequency radio channel.

- To reduce noise and distortion.

- To multiplex more number of signals.

- To increase the bandwidth of the signal.

Types of Modulation

I. Amplitude Modulation

Amplitude of the signal modulated, leaving frequency unchanged.Data is tranferred through altering amplitude.

II. Frequency Modulation

Frequency of the signal modulated, leaving amplitude unchanged.Data is tranferred through altering frequency.