ICube Research Institute, University of Strasbourg, CNRS, UMR 7357, 23 Rue du Loess, CEDEX, 67037 Strasbourg, France.
Sensors (Basel). 2023 Mar 3;23(5):2791. doi: 10.3390/s23052791.
In this paper, two of the most common calibration methods of synchronous TDCs, which are the bin-by-bin calibration and the average-bin-width calibration, are first presented and compared. Then, an innovative new robust calibration method for asynchronous TDCs is proposed and evaluated. Simulation results showed that: (i) For a synchronous TDC, the bin-by-bin calibration, applied to a histogram, does not improve the TDC's differential non-linearity (DNL); nevertheless, it improves its Integral Non-Linearity (INL), whereas the average-bin-width calibration significantly improves both the DNL and the INL. (ii) For an asynchronous TDC, the DNL can be improved up to 10 times by applying the bin-by-bin calibration, whereas the proposed method is almost independent of the non-linearity of the TDC and can improve the DNL up to 100 times. The simulation results were confirmed by experiments carried out using real TDCs implemented on a Cyclone V SoC-FPGA. For an asynchronous TDC, the proposed calibration method is 10 times better than the bin-by-bin method in terms of the DNL improvement.
本文首先介绍并比较了两种最常用的同步 TDC 校准方法，即逐 bin 校准和平均 bin 宽度校准。然后，提出并评估了一种新颖的异步 TDC 鲁棒校准方法。仿真结果表明：（i）对于同步 TDC，应用于直方图的逐 bin 校准不会改善 TDC 的微分非线性（DNL）；然而，它会改善其积分非线性（INL），而平均 bin 宽度校准则显著改善了 DNL 和 INL。（ii）对于异步 TDC，通过应用逐 bin 校准，DNL 可以提高 10 倍，而所提出的方法几乎与 TDC 的非线性无关，可以将 DNL 提高 100 倍。使用在 Cyclone V SoC-FPGA 上实现的实际 TDC 进行的实验验证了仿真结果。对于异步 TDC，在所提出的校准方法中，DNL 改善的程度比逐 bin 方法要好 10 倍。
