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AS5130

Datasheet - Application In form atio n

8.4 Accuracy of the Encoder System

This section enlightens on the individual factors that influence the accuracy of the encoder system, and provides techniques to improve them.

Accuracy is defined as the difference between measured angle and actual angle. This is not to be confused with resolution, which is the smallest

step that the system can resolve. The two parameters are not necessarily linked together. A high resolution encoder may not necessarily be

highly accurate as well.

8.4.1 Quantization Error

There is however a direct link between resolution and accuracy, which is the quantization error:

Figure 25. Quantization Error of a Low Resolution and a High Resolution System

The resolution of the encoder determines the smallest step size. The angle error caused by quantization cannot get better than ± ½ LSB. As

shown in Figure 25, a higher resolution system (right picture) has a smaller quantization error, as the step size is smaller. For the AS5130, the

quantization error is ± ½ LSB = ± 0.7º

high

resolution

low

resolution

error

+1/2 LSB

-1/2 LSB

+1/2 LSB

-1/2 LSB

digitized

function

digitized

function

ideal function

ideal function

Quantization

Error