用于脉冲涡流检测的变频信号源设计

设计了用于脉冲涡流检测的变频信号源系统，其输出频率在100～3000Hz内精确可调，主要用于2～10mm深度的飞机内层结构缺陷的检测。系统采用单片机软件进行数字调频，从而省去了传统的专用调频电路，使软件代替了硬件，降低了硬件成本，简化了硬件结构。软件设计采用中断技术控制数据采集和A／D转换，避免了不必要的重复，提高了控制精度。Proteus仿真结果表明，系统设计正确、运行可靠。

Design for Signal Source of Variable Frequency used in Pulse Whirlpool Test

The signal source system of variable frequency was designed in this paper,the output frequency of the system can be adjusted in the range of 100-3 000Hz. The system can meet the demands of defects test in the depth of 2-10mm on inner structure of airplane. In the design of the system,software of single chip was used to conduct digital frequency modulation. Consequently, traditional circuit of dedicated frequency modulation was replaced by soft, by this method the hardware cost can be decreased and the structure can be simplified. In the design of software, interrupt technique was employed to control data collection and A/D change,by this can avoid repetitive operation meanwhile can increase the control precision. The Proteus emulation results show that the design is right and the system work reliably.