分析了高精度数字时间间隔测量方法的优缺点,提出一种脉冲计数与相位延迟内插相结合的新型时间测量方法.由脉冲计数法保证大的动态测量范围,并设计双边沿计数器提高脉冲计数法的测时精度,降低计数量化误差.通过n次相位延迟内插将测时分辨率提高到量化误差的1/2n.在Xilinx Virtex 5平台上实现了参考时钟16次相位延迟内插与脉冲计数相结合的飞行时间测量系统,测试结果表明,基于FPGA的高精度回波飞行时间测量方法得到的测量误差能优于55 ps.%A new high-precision echo flight time of measuring algorithm was presented by analyzing the advantages and disadvantages of high-precision digital time interval measuring algorithms, which combines the pulse counting method with the phase delay interpolation. The pulse counting method is used to ensure a large dynamic measuring range, and the double-edge triggering counter is designed to improve the accuracy and reduce the counting quantization error. The phase delay interpolation is used to reduce the quantization error of pulse counting for further improving the time measurement resolution. A n-fold phase delay interpolation was performed to raise the time measurement resolution to 1 /2n of the quantized error. Test data show that the echo flight time measurement system with this algorithm as its core and implemented on Xilinx FPCA has a shorter conversion time, and a measured error is less than 55 ps.
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