https://blog.gongquiz.com/2022/09/22/%ec%b4%88%ec%9d%8c%ed%8c%8c%ed%83%90%ec%83%81%ec%8b%9c%ed%97%98%ec%8b%9c-%ea%b0%90%ec%87%a0%ea%b8%b0attenuator%eb%8a%94-%ec%96%b8%ec%a0%9c-%ec%82%ac%ec%9a%a9%ed%95%98%eb%8a%94%ea%b0%80-%ec%b4%88/