General Analysis of Resolution Enhancement on Time-Synchronized Sampling and its Multi-Resolution Solution in 20GSPS Acquisition System

Multiple resolutions have become a new feature required in ultra-fast data acquisition systems (UF-DASs) for various high-end applications, especially for large-scale physical experiments and radar equipment. However, plenty of repetitive efforts are paid to build various UF-DASs with different resolutions for many similar purposes. In this paper, a system-level sampling solution featuring multi-resolution is explored for UF-DASs to make the trade-off between accuracy and speed. Firstly, a resolution enhancement mechanism based on a time-synchronized sampling technique is studied more generally with probabilistic and statistical theory, and its applicable premise is discussed quantificationally at the same time. Then, a hardware-based reconfigurable structure for the purpose of multi-resolution high-speed sampling is discussed with the combination of time-interleaved and time-synchronized sampling methods. Furthermore, to verify the proposed theory, a prototype with a maximal 20GSPS sampling rate and different resolutions of 8,9,10-bit is established. The experimental results show that three vertical resolutions of 8, 9 and 10-bit are achieved in the same prototype, and the effective-number-of-bit (ENOB) in the two higher resolution modes has been improved remarkably from a single low-resolution analog-to-digital converter (ADC). Therefore, the proposed theory and multi-resolution sampling solution are important guides to the resolution trade-off requirement in ultra-fast acquisition systems.