中文摘要：

为了满足脉冲式电子顺磁共振谱仪中电子自旋-核自旋双共振模块的需要,利用直接数字合成器设计并制作了射频信号源.该部件产生的射频脉冲具备对频率、幅度和相位快速精确调制的能力,对原子核自旋有较强操控能力.

英文摘要：

As a part of a pulsed electron paramagnetic resonance（EPR） spectrometer,a RF source based on direct digital synthesis（DDS） was developed and to generate RF pulses that are necessary for electron nuclear double-resonance（ENDOR） experiments.This RF source can generate RF pulses with fast-and accurately-modulated frequency,amplitude and phase,thus providing strong capacity to control nuclear spins.