Design and Implementation of High-performance Lock Preamplifier for High-Field Nuclear Magnetic Resonance Spectrometers

摘要：

In this paper,based on the field-frequency lock technology commonly used in the current commercial nuclear magnetic resonance spectrometers to maintain the magnetic field homogeneity and the theory of weak signal detection,a lock preamplifier at the front-end of lock channel is designed and implemented. The preamplifier consists of broadband amplifier,RF switch and attenuation circuits. In the 20-200 MHz the fabricated preamplifier exhibits a gain of 53 dB and in-bandfluctuation of I dB. The whole noise figure of receiving channel is about 1.5 dB. The delay of RF switch is less than 220 ns. For the transmitter channel the total attenuation range is 30 dB with a 2.0 dB minimum step size. Compared with the lock preamplifier of the commercial spectrometers,the developed preamplifier shows a lower noise figure,a smaller in-band fluctuation and a shorter delay of the switch. Therefore the preamplifier can be applied to nuclear magnetic resonance spectrometers from 200 MHz to 900 MHz.

关键词： NMR lock preamplifier field-frequency lock technology.

作者: Chunliang Dai Changhong Bao Huijun Sun Zurong Ni Zhong Chen

作者单位: Department of Physics,University of Xiamen,Xiamen,361005,China

会议类型: 国际会议

会议名称: 2009 9th International Conference on Electronic Measurement & Instruments(第九届电子测量与仪器国际会议 ICEMI2009)

会议地点: 北京

会议语种:英文

页码: 756-760

在线出版日期: 2009-08-16（万方平台首次上网日期，不代表论文的发表时间）