Integral non-linearity
Integral non-linearity , INL for short , is a characteristic value of analog-to-digital converters (ADC) or digital-to-analog converters (DAC).
The integral non-linearity describes the deviation of the transfer function of the converter from an ideal straight line. This straight line can either go through
- The ideal approximation of the output characteristic with a straight line, the exact course of which is usually undefined
or
- Connection of the highest and lowest data point
are formed. Offset and slope errors should be factored out before calculating the INL.
The integral non-linearity indicates the deviation of the output value from the ideal output value and is specified in LSBs . It corresponds to the difference between the ideal output value and the actual output value and can be calculated using an analog-digital converter
![{\ displaystyle \ mathrm {INL (D)} = \ left ({\ frac {V \ left [D \ right] -V \ left [0 \ right]} {V_ {LSB, ideal}}} - D \ right )}](https://wikimedia.org/api/rest_v1/media/math/render/svg/05dd59a77518bc7ee947097d2445e109d3c42efc)
with the digital output value for the input voltage , the input voltage for the digital output value 0 and the voltage that results in a change in an LSB in the output signal (idealized). For digital-to-analog converters, the observation can be carried out identically using the output voltages and the INL can be calculated from this.
![{\ displaystyle V \ left [D \ right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/3d8fb451917299a298264e7fdb5bdb5de25853b2)
![{\ displaystyle V \ left [0 \ right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f2cc04989ec5c0e1f82e31586aca1d5cca8458f7)
Since any non-linearity in the measurement causes a distortion, the integral non-linearity also influences the dynamic performance of an ADC or DAC.