Analog-to-Digital Conversion › lesson 16 of 100 · Beginner

Calculate Quantization Error

This lesson is part of the Analog-to-Digital Conversion course, and after completing it, you will be able to calculate the magnitude of quantization error in an ADC. The lesson builds on previous topics, such as understanding the input voltage range, and will be used in later lessons, such as describing the ADC transfer function.

The magnitude of quantization error in an ADC can be calculated using the step size and the number of bits.

For example, in a 12-bit ADC with a reference voltage of 5V, the step size is 5V / 2^12 = 1.22mV. The quantization error is the difference between the actual input voltage and the closest quantized voltage, which is half of the step size, or 0.61mV in this case. This error is inherent in the ADC process and can be calculated using the formula: quantization error = (1/2) · (Vref / 2^n), where Vref is the reference voltage and n is the number of bits.

The step size is the smallest voltage change that can be detected by the ADC, and it is determined by the reference voltage and the number of bits. The step size is calculated as Vref / 2^n, where Vref is the reference voltage and n is the number of bits.

The number of bits also affects the quantization error, as a higher number of bits results in a smaller step size and therefore less quantization error.

예시

• A 10-bit ADC with a reference voltage of 3.3VStep size = 3.3V / 2^10 = 3.25mV, quantization error = (1/2) · 3.25mV = 1.625mV
• A 14-bit ADC with a reference voltage of 10VStep size = 10V / 2^14 = 0.61mV, quantization error = (1/2) · 0.61mV = 0.305mV

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