Motivation System Design Experiments Conclusions Real World Signals 464 Time (seconds) Sound frequency 17~22 kHz->wavelength 1.5~2 cm Path length change of wavelength>phase change of 2m 。Move1.25mm→path length change2.5mm→phase changeπ/4 。Phase change direction→movement direction 日，+司1三13卡三分Q0 720Motivation System Design Experiments Conclusions Real World Signals 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 −300 −200 −100 0 100 200 300 Time (seconds) I/Q (normalized) I Q −200 −100 0 100 200 −300 −200 −100 0 100 I (normalized) Q (normalized) Starting (4.04s) Static vector Ending (4.64s) Dynamic vector • Sound frequency 17 ∼ 22 kHz → wavelength 1.5 ∼ 2 cm • Path length change of wavelength → phase change of 2π • Move 1.25 mm → path length change 2.5 mm → phase change π/4 • Phase change direction → movement direction 7/20