Fig. 1. Operating principle of quadrant detector

Fig. 2. Stimulation curves of position resolutions for two models with different radii when total signal-to-noise ratio is 66.44 dB

Fig. 3. Stimulation curves of differences of position resolutions between two models when total signal-to-noise ratio is 66.44 dB

Fig. 4. Stimulation curves of position resolutions for different total signal-to-noise ratios. (a) Linear ordinate; (b) logarithmic ordinate

Fig. 5. Photo of experimental system

Fig. 6. Comparison between experimental results and stimulation curves when ω=0.74 mm

Fig. 7. Comparison of error curves between AM and PM models when ω=0.74 mm

Fig. 8. Calculated values of x0 at position of (0.4 mm, 0 mm) when total signal-to-noise ratio is 66.96 dB

Fig. 9. Calculated values of x0 at position of (0.4 mm, 0 mm) when total signal-to-noise ratio is 86.75 dB