40MHz射频信号源的设计与分析

Design and analysis of 40MHz radio-frequency signal source

直接数字频率合成(DDS)是研制信号源的关键技术。采用DDS技术,设计了输出频率范围为5MHz～40MHz,频率步长为1MHz的射频信号源。首先,分析了其相位噪声和杂散。然后通过传统制板工艺制作了PCB板,使用安捷伦公司频谱分析仪E4403B对其进行了测试,测试结果表明:40MHz射频信号源偏离100kHz处的相位噪声约为-112dBc/Hz,在20MHz带宽内杂散约为-73dBc。

Direct digital synthesis （DDS） is an essential technology in the design of signal source. The design of a radio-frequency signal source with the output frequeneies（5MHz-40MHz） and 1MHz frequency step based on DDS technology is proposed. Firstly, the phase noise and spurs of the radio-frequency signal source are analyzed. Secondly, an experimental radio-frequency signal source circuit is fabricated by traditional PCB process and measured by the Agilent spectrum analyzer-E4403B. The measurement results show that the phase noise is about -112dBc/Hz @100kHz and the spurs is about -73dBc in 20MHz frequency range.