摘要
本文根据时钟数字移相原理,提出了一种新的瞬时测频方法,适用于捷变频雷达测频系统。该方案利用FPGA芯片内部的PLL产生了4路同频率但不同相位的移相时钟,结合等精度测频的原理,在实际闸门开启时段分别对每路时钟的脉冲个数计数,通过计数值相加和计算获得标准时钟计数值,等效为将单路标准时钟的频率提高4倍。实验板验证结果表明,该方案电路简单、成本低、性能稳定,能满足技术指标要求。
In the text, a novel instantaneous frequency measure module, which is applicable for the frequency measure system of frequency hopping radar, is presented based on the digital phase-shift clocks. The module generates 4-routes phase-shifted clocks with the same frequency but not the phase by the PLLs in FPGA, and records the generated clocks' pulse numbers during the measuring process by 4 counters according to the measure theory with uniform precision. At the same time the adder in FPGA adds the all numbers. This method raises 4 times the frequency of counter's clock equally and results a simple electric circuit, a low cost and a stable function while satisfying the technique index required.
出处
《电子测试》
2008年第6期69-73,共5页
Electronic Test
关键词
时钟内插
时钟移相
PLL
脉内测频
clock iinterpolating
clock phase shift
PLL
the frequency measure of radar pulse