为了克服传统电离层垂测仪射频信号软件延时的缺点,提高大气电离层垂测仪系统信号源产生信号的精度,更充分地研究电离层物理特性,利用DDS技术和嵌入μC/OS-Ⅱ操作系统的miniARM微处理器,给出了一个新型的电离层垂测仪系统信号源的架构方案;该系统利用了32位ARM嵌入式微处理器LPC2220的定时器匹配硬件功能,控制DDS芯片Q2368完成无延时的相位调制;实验结果表明,该信号源所产生的高频信号具有精度高,频率转换时间短等特点,其他信号也完全满足电离层垂测仪对信号源的技术要求。
In order to overcome the disadvantage of software delay in traditional HF signal sources and improve the accuracy of HF Signal and research the physical properties of ionosphere, this paper develops a scheme for constructing HF signal sources for ionospheric vertical sounding instrument by using DDS technology and miniARM with embedded system μC/OS-Ⅱ. The design takes advantage of the hardware features of the timer matching of the 32 ARM to accomplish the control of the phase modulation without time--lapse. The experimental results reveal that the realized signal sources have the merits such as high signal precision and short frequency transition time and the other signals can also absolutely meet the technical demands for ionospheric vertical sounding instrument.