摘要
设计了一种由直接数字频率合成(DDS)、倍频链构成的三次变频直接频率合成方案,实现了低相噪捷变频高分辨率毫米波雷达频率合成器设计。利用直接频率合成器的倍频输出取代传统三次变频毫米波频率源的锁相环(PLL),同时提供线性调频(LFM)信号,优化DDS和变频方案的频率配置关系。利用FPGA电路进行高速控制,较好地解决了毫米波频率合成器各技术指标之间的矛盾。实测结果表明,采用该方案的毫米波频率合成器在本振跳频带宽为160 MHz时,线性调频频率分辨率可达0.931 Hz,最大频率转换时间小于2μs,最大杂散低于-60 dBc,相位噪声优于-90 dBc/Hz。
In this paper, an approach of developing high agility and resolution millimeter-wave synthesizer architecture without using PLL （Phase Locked Loop） is proposed. Using the frequency multiplying of DDS output signal to provide the local oscillators instead of PLL in traditional three frequency conversions scheme, with good frequency configuration and optimal utilization of DDS （Direct Digital Synthesizer）, and high-speed controlling of FPGA, the synthesizer implemented with good spectrum purity has exce^- lent performance of both high agility and resolution. The measurement results show that , the millimeter-wave local oscillator＇s band- width is 160 MHz and the minimum frequency step is 0.931 Hz, the maximum frequency switching time is less than 1 μs, the spurious level is better than -60 dBc, the phase noise level is better than -90 dBe/Hz@l kHz.
出处
《电子技术应用》
北大核心
2011年第10期56-59,共4页
Application of Electronic Technique
基金
国家自然科学基金(60801024)
