摘要
高速数据采集电路的设计是实现核磁共振信号数字化获取的关键。本文描述了一个以数字信号处理器( DSP)系统为核心 ,以高速流水线式 A/D转换器、可编程逻辑门阵列 ( FPGA)、数控振荡器 ( NCO)为主体的核磁共振测井用高速数据采集系统。它根据核磁共振测井数据采集频率高 ,但具有间歇性的特点进行了专门设计 ,使用两片先入先出队列芯片 ( FIFO)进行 A/D转换数据的缓冲 ,提高了系统对突发性数据的采集能力。并且使用两片 FIFO交替写入数据的方式 ,为在 DSP中实现数字正交检波提供了便利。该系统理论上具有每 0 .0 5 μs进行一次 A/D转换的能力。目前 ,它稳定地进行了每 0 .1μs一次 A/D转换的数据采集实验 ,满足了核磁共振测井系统的要求。
The design of high-speed data acquisition system is essential for the digital acquisition of nuclear magnetic resonance signals. A high-speed data acquisition system with a DSP core and a circuit composed by high-speed pipeline A/D converter, numerically controlled oscillator (NCO) and FPGA is made for nuclear magnetic resonance logging system. According to the high frequency requirement in data acquisition from nuclear magnetic resonance signals, which enjoy the characteristic of intermission, two FIFO chips are used for the A/D data buffering to deal with the contradiction. It improves the ability of acquiring abrupt data for this system. The method of data written alternatively with two FIFO chips offers convenience to realize digital quadrature detection in DSP. Theoretically, this system has the ability of A/D conversion within 0.05μs. Experimental result shows that A/D conversion can be stably accomplished within 0.1μs, which meets the requirements of nuclear magnetic resonance logging system.
出处
《数据采集与处理》
CSCD
2002年第1期69-72,共4页
Journal of Data Acquisition and Processing