中文摘要：

热噪音是到在有一只旋转扭转摆钟的弱等价原则测试的敏感的最基本的限制之一。速度抑制并且内部抑制是在热噪音的二许多贡献，并且哪个主要在低频率限制扭转摆钟，是困难的被实验验证。基于快 Fourier 变换的常规方法，我们建议一个发达方法决定热噪音限制然后获得摆钟运动信号的精确力量光谱密度。实验结果证实热噪音被与高真空的在低频率扭转摆钟实验的在纤维的内部抑制主要贡献。量的数据分析证明在实验的基本噪音水平是大约一～二次内部抑制热噪音的理论价值。

英文摘要：

Thermal noise is one of the most fundamental limits to the sensitivity in weak equivalence principle test with a rotating torsion pendulum. Velocity damping and internal damping are two of many contributions at the thermal noise, and which one mainly limits the torsion pendulum in low frequency is difficult to be verified by experiment. Based on the conventional method of fast Fourier transform, we propose a developed method to determine the thermal noise limit and then obtain the precise power spectrum density of the pendulum motion signal. The experiment result verifies that the thermal noise is mainly contributed by the internal damping in the fiber in the low frequency torsion pendulum experiment with a high vacuum. Quantitative data analysis shows that the basic noise level in the experiment is about one to two times of the theoretical value of internal damping thermal noise.