先用CD4046 + CD4518 锁相倍频1000~10000倍,然后再笃悠悠用CD4518分频计数<br />才10来元的成本哦<br />用硬件测低频这恐怕是唯一的低成本方案了拉,<br />83年我用这个办法测得工频,可显示小数点后3位→50.001Hz<br />不过量程跨一个数量级,4046的低通设计有点玄,有可能需要分段测<br /><br /><br /><img src="https://bbs.21ic.com/upfiles/img/20078/20078276388632.gif"><img src="https://bbs.21ic.com/upfiles/img/20078/20078276388632.gif"><img src="https://bbs.21ic.com/upfiles/img/20078/20078276388632.gif"><img src="https://bbs.21ic.com/upfiles/img/20078/20078276388632.gif"><img src="https://bbs.21ic.com/upfiles/img/20078/20078276388632.gif">
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