基于ARM和CPLD的NMR谱仪前放控制设计

提出了一种基于ARM（Advanced RISC Machine，先进精简指令计算机）和CPLD（Complex Programmable Logic Device, 复杂可编程逻辑器件）的NMR（Nuclear Magnetic Resonance，核磁共振）谱仪前放控制系统设计方案. 该控制系统以ARM为控制核心、 CPLD为控制命令执行单元， 控制前置放大器和混频器的工作状态. 本电路包括以下主要功能：1) 前置放大器收发切换的门控信号电平转换；2) 氘梯度匀场时身频通道自动切换；3) 探头调谐的信息显示；4) 锁前放和混频器的配置. 该设计方案具有系统运行速度高、 控制灵活和成本低的优点，并且可以有效减小系统噪声，降低控制部件对前置放大器和混频器的干扰.

An ARM- and CPLD-Based Preamplifier Control System for NMR Spectrometers

This paper presented an ARM- and CPLD-based design scheme for the NMR spectrometer preamplifier control system. ARM was used as the center control CPU, and CPLD as the perform unit to control the working conditions of the high-band and broadband preamplifiers, mixer and lock preamplifier. The system developed has the following main functions: 1) to convert the input TTL gate signal levels into +5V/15V signal, which is then used to control the switching between the receiver mode and the transmitter mode of the high-band and broadband preamplifiers; 2) to give users a reference signal for tuning; 3) to relay the switch channels to lock transmitter and broadband receiver in deuterium gradient shimming experiments; and 4) to display the data sent from the console PC or ADC on LED in real-time.