National Instruments Flex II ADC Technology

Single-bit delta-sigma analog-to-digital converters (ADCs) provide high resolution and high dynamic range for low-frequency applications. However, because of limited sampling speeds, single-bit delta-sigma ADCs are not available for applications involving dynamic signals greater than a few hundred kHz in frequency. Multibit delta-sigma ADCs can provide high dynamic range at high frequencies, provided that the ADC can be linearized to remove nonlinearities inherent to multibit delta-sigma ADCs. The National Instruments PXI-5922 flexible resolution digitizer uses multibit delta-sigma ADCs together with patented linearization techniques to provide unprecedented resolution and dynamic range at higher sampling rates. This paper discusses the flexible resolution technology used in the NI PXI-5922 to make it the highest dynamic range digitizer on the market.