Difference between Analog signals and Digital signals

In this topic, you will learn about, Difference between Analog signals and Digital signals.

Analog signals Digital signals
Analog signals are difficult to get analyzed at first. Digital signals are easy to analyze.
Analog signals are more accurate than digital signals. Digital signals are less accurate.
Analog signals take time to be stored. It has infinite memory. Digital signals can be easily stored.
To record an analog signal, the technique used preserves the original signals. In recording digital signals, the sampled signals are taken and preserved.
There is a continuous representation of signals in analog signals. There is a discontinuous representation of signals in digital signals.
Analog signals produce too much noise. Digital signals do not produce noise.
Examples of analog signals are Human voice, Thermometer, Analog phones, etc. Examples of digital signals are Computers, Digital Phones, Digital pens, etc.

Conversion of Analog signals to Digital signals

Most of the image sensors are in the analog signal, and digital processing cannot be applied to it, as it requires infinite memory to store because signals have an infinite value that is why we cannot store it. To create a digital image we can convert data into digital form.

For the conversion there are two steps:

  1. Sampling
  2. Quantization

To convert an analog signal into a digital signal, both its axis(x,y) is converted into digital format.

Convert analog to digital signal

As we can see that image is continuous in its coordinates(x-y).

So sampling deals with digitizing of co-ordinates and quantization deals with digitizing the amplitude.


In analog signals, there are continuous electrical signals that vary with time. With the help of a subsystem, a sampler extracts continuous signals for the sampling of signals.

Sampeling of signal

Sampling is done along the x-axis of signals that continuously differs with time. It is divided into two categories one is sampling and the other is downsampling.

In downsampling, the range of values on the x-axis is always less.


It is a process of image processing, in which continuous and time-varying values of analog signals are divided into non-overlapping discrete and unique values assigned to each subrange.

Sampling and quantization are opposite to each other. Sampling is done along the x-axis but quantization is done along the y-axis.

In image processing, the sampled image is considered as a digital value. When there is a transition of states between time-varying values of image function and its digital equivalent signifies quantization.

Conversion of analog signals to digital signalsThe main problem in the image is the continuous occurrence of false contours which can be quantized later with inadequate brightness levels.
The fine shading of the image depends on the level of quantization.

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