文章研究了直接数字合成DDS(Direct Digital Synthesis)技术.DDS技术是一种创新的电路体系结构,它是将先进的数字处理理论与方法引入信号合成领域的一项新技术.在对DDS技术进行了详细分析研究后,最后在CPLD上进行了布局布线和后仿真,并...文章研究了直接数字合成DDS(Direct Digital Synthesis)技术.DDS技术是一种创新的电路体系结构,它是将先进的数字处理理论与方法引入信号合成领域的一项新技术.在对DDS技术进行了详细分析研究后,最后在CPLD上进行了布局布线和后仿真,并通过了CPLD的原理样机的测试.展开更多
直接数字式频率合成（Direct Digital Synthesizer, 编写DDS）是近年来出现的一种频率合成的新方法，由于采用了全数字化技术，它具有分辨力高和快速换频的突出优点，在仪表、雷达、扩频通信等方面得到了广泛的应用，由于器件原因，还...直接数字式频率合成（Direct Digital Synthesizer, 编写DDS）是近年来出现的一种频率合成的新方法，由于采用了全数字化技术，它具有分辨力高和快速换频的突出优点，在仪表、雷达、扩频通信等方面得到了广泛的应用，由于器件原因，还存在一些缺陷、有待改进。本文介绍了DDS的原理，分类及改进方案；对DDS的目前水平作了分析，具体介绍了一些集成产品以及应用，随着高速数字器的进一步发展，加上各种组合方案的优化设计，将会得到高速、低功耗，低价格的频率合成器。展开更多
Based on the synthesis of DDS in fluidization bed,a new method that can remarkably enhance reactivity and selectivity of the copper-silicon contact mass is investigated experimentally. DDS is produced from silicon and...Based on the synthesis of DDS in fluidization bed,a new method that can remarkably enhance reactivity and selectivity of the copper-silicon contact mass is investigated experimentally. DDS is produced from silicon and methyl chloride at about 300?℃in the direct synthesis process. The catalyst used in this reaction system is active cuprous chloride powder,which usually forms conglomeration of powder. The conglomerate of catalyst is known to be harmful to the synthesis reaction. Treated by ultrasonic energy,conglomeration of active cuprous chloride catalyst is destroyed,so as to achieve better proportioned dispersion of silicon and catalyst powder. By this means, CuCl catalyst is distributed evenly on the surface of silicon powder, thereby reaction activity and selectivity are increased in the synthesis process of DDS. Using ultrasonic dispersion achieves the same reaction activity with smaller catalyst dosage than the normal dispersion method.展开更多
文摘直接数字式频率合成（Direct Digital Synthesizer, 编写DDS）是近年来出现的一种频率合成的新方法，由于采用了全数字化技术，它具有分辨力高和快速换频的突出优点，在仪表、雷达、扩频通信等方面得到了广泛的应用，由于器件原因，还存在一些缺陷、有待改进。本文介绍了DDS的原理，分类及改进方案；对DDS的目前水平作了分析，具体介绍了一些集成产品以及应用，随着高速数字器的进一步发展，加上各种组合方案的优化设计，将会得到高速、低功耗，低价格的频率合成器。
文摘Based on the synthesis of DDS in fluidization bed,a new method that can remarkably enhance reactivity and selectivity of the copper-silicon contact mass is investigated experimentally. DDS is produced from silicon and methyl chloride at about 300?℃in the direct synthesis process. The catalyst used in this reaction system is active cuprous chloride powder,which usually forms conglomeration of powder. The conglomerate of catalyst is known to be harmful to the synthesis reaction. Treated by ultrasonic energy,conglomeration of active cuprous chloride catalyst is destroyed,so as to achieve better proportioned dispersion of silicon and catalyst powder. By this means, CuCl catalyst is distributed evenly on the surface of silicon powder, thereby reaction activity and selectivity are increased in the synthesis process of DDS. Using ultrasonic dispersion achieves the same reaction activity with smaller catalyst dosage than the normal dispersion method.
