基于锁相环的微波等离子体灯扫频源研究

Study on the Frequency Sweep Microwave Sulfur Light Source Based on Phase Locked Loop

微波等离子体灯是利用微波能激发等离子体发光的新型光源。微波等离子灯射频模块的工作频率是在420～470MHz范围内可调，其输出功率平坦度越小越好。基于锁相环频率合成原理，使用ADI公司的集成芯片ADF4350设计了满足要求的频率源。最终通过设计PCB、制板、电装并调试制作了满足要求的频率源的。最终测试结果表明，输出平均功率为5dBm，功率平坦度小于0．2dB，杂散抑制在50dBc以上。

Microwave sulfur lamp is new light source using microwave plasma. The RF module＇s fre- quency is working from 420 MHz to 470 MHz and the power flatness smaller is better. Using the integrat-ed phase locded loop（PLL） chip ADF4350 designed the sweep signal source which meet the requirements based on the theory of PLL synthesizer. The frequency is finally completed after PCt~ designing, circuit board manufacturing, assembling and debugging. The final test results show that the average power is 5 dBm, power flatness is less than 0.2 dB and the spurious suppression is above 50 dBc.