核磁共振谱仪数字接收机的原理与实现

THE PRINCIPLE & IMPLEMENT OF DIGITAL RECEIVER FOR NMR

核磁共振波谱仪射频系统数字化是现代核磁谱仪的发展方向 ,用数字检波技术代替模拟正交检波是数字接收机的一项新技术 .本文在分析模拟正交检波原理与不足的基础上 ,介绍了数字正交检波、过采样和采用中频直接采样的原理 ,及在 40 0MHz核磁谱仪上的实现方案 .

The digitalization for RF system of NMR spectrometer is the improvement of modern NMR spectrometer, and the replacement for analog quadrature phase detection with digital phase detection is a new technology for digital receiver. After analyzing the principle and difficulties of analog QPD receiver, the article introduces the principle of digital QFD, oversampling and IF sampling, and the implement of digital receiver on MSL 400 spectrometer.