Research Of The Testing Of The Analog-to-Digital Converter's Parameters

Analog to digital converter is a chip which is used to convert the voltage input to digital output in bit. In this way, we can deal with some signals which are continual and analog by computer. So ADC is used in many aspects. Because in many instruments ADC is the most significant part, it is very important to evaluate the performance of ADC exactly. The static and dynamic parameters are the standard to evaluate it. The static parameters include integrated nonlinearity,differential nonlinearity, and the dynamic parameters include signal-to-noise ratio,signal-to-noise+distortion ratio,equivalent number of bits,total harmonic distortion,spurious-free dynamic range,two-tone intermodulation distortion,multi-tone intermodulation distortion.We have to use the dynamic test if we want to get the performance of ADC exactly. And the key point of exactness is the integrity of the signal. The interfix sample makes the sample of full period come true. But in fact we need to satisfy the conditions of interfix sample. Because of the improving of the ADC resolution, it is difficult to satisfy these conditions. Now we use the windows function to instead of the interfix sample. So we can reduce the leakages. The analysis of error solves the emergence of error during the test which will effect the result of test. In the article below, I use the way of code density and FFT frequency analysis. By the help of logic analyzer 16702B of Agilent, I finish the test of static and dynamic parameters.