A practical implementation of dynamic testing of an AD converter

Abstract

This paper presents a practical testing system which can measure the dynamic parameters such as effective bits (EB), signal to noise ratio (SNR), differential and integral nonlinearity (DNL and INL) of an AD converter. For practical implementation we propose a mixed frequency estimation algorithm with weighted least square method to estimate the EB. Furthermore we combine the spectral average method with frequency domain estimation to measure the SNR and use the histogram method to calculate the DNL and the INL. For practical purpose, we choose a logical analyzer as the high speed data acquisition device and a PC as the instrument controller. Two programmable signal generators with very low harmonic distortion are used for signal source of the ADC Testing. All the instruments are controlled by the PC through GPIB with a test software. Finally we apply the proposed test system and algorithm to measure the dynamic parameters of a real ADC (Datel ADC-HS12B). Results show that the proposed test system and methods are fast and accurate. Users can test the ADC automatically without worrying about the expensive testing instruments, interface problems and complex algorithms which may occur in other ADC testing systems.