Resolution improvement in an analog‐to‐digital converter by the superposed dither signal
Resolution improvement in an analog‐to‐digital converter by the superposed dither signal
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通过叠加抖动信号提高模数转换器的分辨率
DOI：
10.1002/ecja.4410641202
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
N. Takeuchi
中科院分区：
文献类型：
--
作者：
H. Shimizu;Y. Iikura;Y. Sasano;N. Takeuchi
本文讨论了一种提高模数转换器分辨率的方法，以检测输入信号中小于1 LSB（最低有效位）的差异。通过在输入信号上叠加抖动并对多个测量值取平均值，可以提高分辨率。本文介绍了这种方法的理论和实验验证。
该分析在输入信号上叠加抖动的情况下，数值计算A-D转换结果的期望值和方差的期望值。结果表明，抖动幅度越大，A-D转换的期望值越接近真实的值，方差的期望值越大。
作为测量次数的函数，计算了抖动幅度与分辨率提高之间的关系。例如，当测量次数为100次且抖动幅度为0.4 LSB时，分辨率可提高至0.05 LSB。
用白色噪声发生器作为抖动源，直流电压标准作为信号源，瞬态记录仪作为A-D转换器，对这一分析进行了实验验证。
This paper discusses a method to improve the resolution of an analog-to-digital (A-D) converter to detect differences less than 1 LSB (least significant bit) in the input signal. Resolution is improved by superposing dither on the input signal and averaging over many measurements. The theory and experimental verification for this method are described.
This analysis calculates numerically the expectation value of the result of A-D conversion and the expectation value of the variance, with the dither superposed on the input signal. The results show that for larger amplitude of dither, the expectation value of A-D conversion comes closer to the real value, and the expectation value of the variance becomes larger.
The relation between the amplitude of dither and the improvement of resolution is calculated as a function of the number of measurements. For example, when the number of measurements is 100 and the amplitude of dither is 0.4 LSB, the resolution can be improved to 0.05 LSB.
This analysis is verified experimentally by using a white noise generator as a dither source, dc voltage standard as a signal source, and a transient recorder as an A-D converter.