Influence of the environmental noise on determining the period of a torsion pendulum*
Luo Jiea), Tian Yuana), Shao Cheng-Gangb)†, Wang Dian-Honga)
       
The rotational angle (a) and its power spectral density (b): the PSD of the thermal noise is plotted by the solid line, while that of the signal is plotted by the dash line.