https://blog.wongcw.com/2022/06/13/%e6%a5%b5%e6%98%9f%e9%96%8b%e5%a7%8b%e5%90%91hertz%e4%ba%a4%e4%bb%98%e9%9b%bb%e5%8b%95%e6%b1%bd%e8%bb%8a/