【摘要】 直接数字合成（ＤＤＳ）是近年来迅速发展起来的一　种新型信号合成技术。由于采用了全数字结构，它具有频率和相位分辨率高、频率转换速度　快、相位噪声小以及易于集成等诸多优点。文章首先介绍了ＤＤＳ的原理，然后就其在低场核　磁共振岩心分析仪中的应用进行了详细的讨论，对应用效果进行了总结。测试表明，将ＤＤＳ　用于低场核磁共振岩心分析仪是很成功的。更多还原

【Abstract】 Direct digital synthesis (DDS) is a new signal synthesis technipue developed very fast in recent years. Because of its digital structure, it has many advantages, such as high frepuency and phase resolution , high speed of frequency changing, low phase noise and easy for integration. In this article, the principle of DDS is reviewed at first, then its new application in low field nuclear magnetic resonance core analyzer is discussed in detail. The advantages of the application are summarized. Test shows that the application of DDS in low field nuclear magnetic resonance core analyzer is successful.更多还原