Question

Explain about modulation.

Answer 1

Modulation is nothing but, a carrier signal that varies in accordance with the message signal. Modulation technique is used to change the signal characteristics. Basically, the modulation is of following two types:


Analog Modulation
In analog modulation, the analog signal (sinusoidal signal) is used as a carrier signal that modulates the message signal or data signal. The general function Sinusoidal waves are shown in the figure below, in which, three parameters can be altered to get modulation -they are amplitude, frequency and phase. So, the types of analog modulation are:

Analog Modulation
1. Amplitude Modulation (AM)
2. Frequency Modulation (FM)
3. Phase Modulation (PM)


Digital modulation is used to transfer a digital bit stream over an analog channel at a high frequency. This enables us to transmit signals generated in a digital circuit across a physical medium. This is because digital signals can be handled with higher security and digital systems are readily and widely available.