基于可触发环形振荡器的高精度时间间隔测量

High-precision time interval measurement based on triggerable ring oscillator

提出了一种新的高精度时间间隔测量方法,该方法利用代表事件的短脉冲去触发一个高速环形振荡电路,产生一个与该事件同步的时钟信号,该时钟信号随后被用作模-数转换器(ADC)的采样时钟去采样一个正弦参考信号。因此,两个事件之间的时间间隔被映射成正弦参考信号上的两个点之间的初始相位差,随后对有限数量的样本进行全相位快速傅里叶变换(apFFT)运算,准确地计算出这个初始相位差,进而可以准确获得两个事件之间的时间间隔。该测量方法降低了工程实现的难度,当正弦参考信号的频率为10MHz,ADC的采样频率为133MHz、分辨率为12bits,apFFT运算点数为4096时,可以获得约2.8ps rms的单次测量精度和约Ips的时间分辨率,误差分布接近正态,实验结果与基于理论分析的误差范围一致。

Anovelhigh-precision time interval measurement method is proposed in this paper. The short pulse is utilized to representthe event to trigger a specially designed high-speed ring oscillator circuit. In this way, the clock signal is generated, which issynchronized with the event.lt is subsequently adoptedas the sampling clock of ADC to sample thesinusoidal reference signal. Accordingly, the time interval between the two events is mapped to the initial phase difference between the two points on the sinusoidal reference signal. The all-phase fast Fourier transform (apFFT) algorithm is performed on a finite number of samples to accurately determine the initial phase difference.Then, the accurate time interval between the two events is achieved. The proposed method reduces the difficulty of engineering implementation and increases the reliability and practicability of the measurement. In the case of a sinusoidal reference signal with 10 MHz frequency, a 12-bit ADC with 133 MHz sampling frequency, and apFFT with operation point number N=4 096, the single-shot time interval measurement precision of 2. 8 ps rms and time resolution of about 1 ps can be realized. The error distribution is close to normal distribution. Experimental results are in agreement with the error budget of the theoretical analysis.