## 4 Experiment
### Turntable Speed Measurement Experiment  
The experimental scenario depicted in Figure 9a was devised to ascertain the efficacy of CWDL spectral leakage mitigation through the incorporation of the HSCW. In this experiment, a motor with a turntable is positioned 40 m in front of the CDWL optical system to address the blind zone issue inherent to pulse CDWL, which arises from the reflection off the fiber end face. By adjusting the rotational speed and steering the motor to generate different sizes of Doppler shifts, the test results in the simulation experiments are verified by comparing the frequency inversion results of adding a RW and a HSCW window in the same distance gate. Figure 9b depicts the CDWL laser vertically illuminated on the side of the turntable with a diameter of 30 cm and an incidence angle of 45\({}^{\circ}\).  
The experiment was conducted using the upper computer to control the rotational speed steering of the turntable. The data underwent 300 instances of incoherent spectrum accumulation following the preprocessing of the RW and HSCW. Subsequently, the velocity inversion results were obtained by employing the energy center of gravity method for spectrum correction. The radial component of the average speed of the turntable during rotation was found to be 4.733 m/s, 4.233 m/s, 3.835 m/s, 2.637 m/s, 1.405 m/s, \(-\)0.107 m/s, \(-\)1.102 m/s, \(-\)1.02 m/s, \(-\)2.114 m/s, \(-\)3.127 m/s, \(-\)4.569 m/s, and \(-\)5.124 m/s. The experimental velocity inversion results are shown in Figure 10. In Figure 10, the scatter plot represents the relationship between the actual and measured velocities. The horizontal coordinate of the plot represents the actual turntable radial velocity, the vertical coordinate represents the inverted velocity value after the window function processing, and the red line in the plot represents the result of linear fitting between the actual and measured velocities. The light red area represents the error band of velocity inversion.  
\begin{table}
\begin{tabular}{c c} \hline
**Parameters** & **Value** \\ \hline Wavelength/nm & 1550 \\ Sampling Frequency/MHz & 250 \\ Pulse Width/ns & 200 \\ Repetitive Frequency/kHz & 20 \\ Single Pulse Energy/\(\upmu\)J & 12 \\ Range Gate Resolution/m & 38.4 \\ Wind Speed range/m\(\cdot\)s\({}^{-1}\) & \(-\)31–31 \\ \hline \end{tabular}
\end{table}
Table 1: CDWL prototype parameters.  
Figure 9: Turntable experiment scenario: (**a**) experimental scenario and the distance between the locations of equipment; (**b**) the irradiation angle of the laser beam.  
In comparison with the conventional RW function, the incoherent accumulated velocity inversion results obtained through the incorporation of the window function pre-processing demonstrate a closer alignment with the actual velocity outcomes. In order to further analyze the measurement accuracy of the four window functions, the RMSE of the experimental results is compared and analyzed, as shown in Figure 11.  
This figure shows that the CDWL velocity inversion accuracy is greatly improved after adding the HSCW window function compared with the traditional RW function, and the velocity inversion accuracy of the second-order HSCW window function is even higher compared with the RW and the first-order HSCW. The velocity inversion accuracy under the RW function is 0.481 m/s, and the velocity inversion accuracy after adding the first-order HSCW and the second-order HSCW is 0.214 m/s and 0.173 m/s, respectively.