Data acquisition system based on Time-Interleaved Analog-to-Digital Conversion for Time-of-Flight Mass Spectrometer

摘要

In recent years, the resolution of Time-Of-Flight Mass Spectrometer (TOF-MS) is improved benefiting from space focusing, ion reflectron and orthogonal acceleration techniques. To guarantee a good resolution of the whole system, a high-performance data acquisition system is demanded. According to the requirements of the TOF-MS in National Institute of Metrology P.R. China (NIM), a 2-Gsps, 8-bit data acquisition system is designed, which is based on Time-Interleaved Analog-to-Digital Conversion (TIADC) technique. The Peripheral Component Interconnect (PCI) bus interface is integrated in this system to communicate with the Personal Computer (PC), and the Direct Memory Access (DMA) transfer method is employed to achieve a data transfer rate of 20 MByte/s. Through digital post-processing algorithm, the mismatch errors between different TIADC channels are corrected, which significantly improves ADC's performance. Initial test results indicate that the Effective Number of Bits (ENOB) of this system is better than 7 bit in the input frequency range below 180 MHz, and 6.4 bit in the range from 180 MHz to 500 MHz.