perturbation-based ADC Calibration

[han sang jun]

I would like to know why PN noise samples are put in ADC input. What would happen if PN noise was not added?


I am not good at English. Please forgive my poor expressions.

 

[AMS012]

Any low resolution ADC needs some form of randomness in its input so that the output will not contain any particular tonality compared to its quantization noise power spectral density. To break its tonality, the process of dithering is done by adding some very small (approximately 0.1-0.2LSB) in strength) pseudo random signal at its input. Adding PN of an oscillator or any other circuit would also accomplish the same dithering.

 

[han sang jun]

Your answer is correct. but as i know, dithering has two types: Subtractively dithering, nonsubtractively dithering.
i think, you answer is nonsubtractively dithering. What I'm curious about is subtractively dithering.
I think I need to study more.

anyway, thank you for your answers.