Difference Between Analog and Digital Modulation

Analog vs Digital Modulation

Modulation is the process of modifying one signal based on another, and it is used mostly in the transmission of data from one point to another. Although there are many types of modulation, there are two basic types; analog modulation and digital modulation. The main difference between analog modulation and digital modulation is in the manner that they transmit data. With analog modulation, the input needs to be in the analog format, while digital modulation needs the data in a digital format.

Because of the differences in the input signal, the output signal is also quite different. In analog modulation, any value between the maximum and minimum is considered to be valid. It is not so with digital modulation as only two values are considered valid; one value to represent “1” and another to represent “0.” All other values are considered noise and are rejected.

Because most signals that we transmit are analog in nature, like one’s voice, it is far simpler to do analog modulation than digital. If you want to transmit a voice using digital modulation, you’d need to pass it through an analog-to-digital converter before transmission and a digital-to-analog converter at the receiver to recover the original signal. The additional stages needed for transmitting digital modulation increases both the cost and complexity of the transmitter and receiver.

The major advantage that digital modulation has over analog transmission is how it achieves greater fidelity. With analog modulation, any noise or interference that falls in the given frequency bandwidth gets mixed with the actual signal. Although there are a number of ways to mitigate noise, it will still cause some amount of degradation. Because digital modulation only recognizes 0’s and 1’s, any noise is virtually eliminated once the receiver discerns whether a “0” or a “1” was transmitted. Unless the signal is very badly distorted, the output signal will be literally identical to what was transmitted.

Under both analog modulation and digital modulation, there are a number of other modulation techniques each with its own strengths and weaknesses. But each technique has its basic commonalities of transmitting either a digital or analog signal.

Summary:

1.Analog modulation takes an analog signal while digital modulation takes a digital signal.
2.Analog modulation has a range of valid values while digital modulation only has two.
3.Analog modulation is cheaper to implement than digital modulation.
4.Digital modulation produces more accurate output than analog modulation.

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