一种超宽带等效采样接收机的设计与实现

摘要

脉冲超宽带雷达回波信号由于带宽大而难以直接采样,通常采用等效时间采样方法来进行模数转换.传统的等效采样接收机大都是基于改变ADC采样时钟的时延来实现等效采样,采样时钟对触发信号会产生亚稳态时序,不可避免地会出现数据误对齐,必须添加辅助的在线或离线校正设计.针对这一问题,设计了一种基于FPGA内置延迟线的超宽带等效采样接收机,FPGA产生延时可调的发射触发信号去控制波形产生系统,基于高速采样保持器和ADC完成回波接收,实现了超宽带射频信号的等效采样,而无数据误对齐问题.接收机的等效采样速率为12.8 GS/s,-3 dB采样带宽为6.4 GHz,满足脉冲超宽带雷达的应用需求.%It is hard to directly sample the ultra-wideband radar echoes due to its large bandwidth.The equivalent time sampling method is often used to carry out analog to digital conversion (ADC).Traditional equivalent sampling receivers are mostly based on changing the delay of ADC sampling clock to realize equivalent sampling.Due to the metastable state between sampling clock and trigger signal,the received da-ta is misaligned inevitably and the correction algorithm online or offline must be added.To solve this prob-lem,an ultra-wideband equivalent sampling receiver based on internal delay line of FPGA is designed.Based on the received echoes of high speed sample-and-hold and ADC,the equivalent sampling of ultra-wideband RF signal is realized without data misaligning when using the delay-tunable transmitting signal generating by FPGA to control the waveform generating system.The equivalent sampling rate is 12.8 GS/s and - 3 dB sampling bandwidth is 6.4 GHz,meeting the application requirements of UWB radar.