Quantization and its Types

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In this article, we explained all the important points regarding quantization in detail.

let’s understand the topic:

Quantization is a process of converting discrete time continuous valued signal (discrete time signal) into discrete time discrete valued signal (digital signal). Other definition of quantization, It is the process of mapping the infinite range of continuous values signal to a finite set of discrete values signal or levels.

The device that performs quantization is called Quantizer. Quantifying an continuous analog signal is done by discretizing the signal with a number of quantization levels.

In quantization, the amplitude of sampled signal is round off to the nearest quantized level. This rounding off is known as quantization error. By increasing the numbers of quantization levels we can reduce the quantization error.

Quantization of an Analog Signal

Quantization is a process of ” Rounding off the sampled value to the nearest quantization level”.

Here I explain the step-by-step quantization process of an continuous analog signal.

Steps of quantization

  1. Divide the sampled signal amplitude (voltage range) into L different level.
  2. The number of level or value of L is depend upon “number of bit that encoder can encode” L is given by L= 2n where n is the
  3. The number of level or value of L is depend upon “number of bit that encoder can encode” L is given by L= 2n where n is the number of bit that encoder can encode. If we have 4-bit encoder it means the value of n=4 so we divide the signal amplitude into L=24=8 level.
  4. If the number of level is more the quantization error is less and vice-versa.
  5. The space between two interval is called step size (Δ or S). Step-size (Δ or S )= VH-VL / L where VH is max and VL is lowest value of sampled voltage.
  6. Now, draw mid line at S/2, representing quantization levels.
  7. Now, assign binary codes to each quantization level.

8. Now, calculate the quantization error, which is the difference between the original sampled value and the quantized value. This error represents the loss of information due to quantization.

The figure given below shows how an continuous analog signal gets quantized. Here, the blue line represents continuous analog signal and the brown one represents the quantized signal.

This figure shows the resultant quantized signal which is the digital form for the given analog signal.

This is also called as Stair-case waveform, in accordance with its shape.

Types of Quantization

There are basically two type of quantization