Accurate spectral testing of analog-to-digital converters with frequency drift using phase correction and averaging

Frequency drift is an important issue and is difficult to be avoided in ADC testing. The power leakage caused by frequency drift in the ADC output spectrum cannot be removed by conventional methods. This paper proposes a new algorithm which can estimate the ADC specifications accurately when there is frequency drift. The output of the ADC is collected as Ks segments. Phase correction is applied to those segments to make the initial phase of each segment is zero. And those segments are averaged after phase correction to remove the frequency drift effect. Simulation results show that this algorithm can obtain the ADC specifications correctly when the input frequency drifts under 100ppm/second.