Real-Time Estimation of Zero Crossings of Sampled Signals for Timing Using Cubic Spline Interpolation
Real-Time Estimation of Zero Crossings of Sampled Signals for Timing Using Cubic Spline Interpolation
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DOI：
10.1109/tns.2017.2721103
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发表时间：
2017-06
影响因子：
1.8
通讯作者：
R. Aliaga
中科院分区：
文献类型：
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作者：
R. Aliaga
提出了一种用于定时应用的具有次采样分辨率的采样信号过零点位置的硬件估计方案，该方案包括在过零点附近用三次样条插值信号，然后找到所得多项式的根。提出了一种基于二分法的迭代算法，该算法每步得到一位结果，并采用定点表示法进行有效的数字实现。特别地，根估计迭代仅涉及两次加法，并且可以从具有某些对称性质的有限脉冲响应（FIR）滤波器获得初始值。它示出，这允许在线实时估计的时间戳在自由运行的采样检测器系统与更常见的线性插值的精度提高。使用理想的和真实的定时信号的模拟评估的方法，并估计其实施的资源使用和速度。
A scheme is proposed for hardware estimation of the location of zero crossings of sampled signals with subsample resolution for timing applications, which consists of interpolating the signal with a cubic spline near the zero crossing and then finding the root of the resulting polynomial. An iterative algorithm based on the bisection method is presented that obtains one bit of the result per step and admits an efficient digital implementation using fixed-point representation. In particular, the root estimation iteration involves only two additions, and the initial values can be obtained from finite impulse response (FIR) filters with certain symmetry properties. It is shown that this allows online real-time estimation of timestamps in free-running sampling detector systems with improved accuracy with respect to the more common linear interpolation. The method is evaluated with simulations using ideal and real timing signals, and estimates are given for the resource usage and speed of its implementation.