Apparatus and method for testing linearity of an analog to digital converter

An apparatus for testing linearity of an analog to digital converter, comprising:

• a controller that outputs a sampling frequency clock that is used to convert an analog signal into a digital signal having digitized code value, that digitally filters the digitized code value to provide a filtered code value according to a stored program, that generates a histogram based on the filtered code value, and that provides control to display the histogram;
• a signal generator that generates a ground voltage and an analog triangular wave signal;
• an analog to digital converter that converts the analog triangular wave signal generated by said signal generator into the digital signal and that outputs the digital signal;
• a memory that stores the digitized code value of the digital signal provided by said analog to digital converter and that outputs the stored digitized code value to said controller for digital filtering, under control of said controller;
• and
• a display that displays the histogram generated by said controller, under control of said controller.

A method of testing linearity of an analog to digital converter, comprising:

• generating a ground voltage;
• converting the ground voltage into a digital voltage value using the analog to digital converter;
• determining a filter order responsive to the digital voltage value;
• generating a digital filter value based on the determined filter order;
• converting an analog triangular wave signal into a digital code value using the analog to digital converter;
• digitally filtering the digital code value using the generated digital filter value, to eliminate noise from the digital code value;
• and
• generating a histogram responsive to the filtered digital code value, to analyze linearity of the analog to digital converter.