本文介绍两个实用的频率比较器.它们线路简单,使用起来就像电压比较器那样方便.在输入端加上两个不同频率的信号时,线路将根据二者频率偏差的方向,输出“1”或“0”. 图1所示的频率比较器只用了三块电路:两块CH4024(七级二进制加法计数器,作分频用)和一块CO39(四组二输入端或非门).f_??和f_R分别代表输入频率和基准频率(当然两者可以交换,不过输出极性相反).因为两个分频器的接法完全相同,所以,在计数 This article describes two practical frequency comparators that have simple circuitry and are as easy to use as voltage comparators. When two different frequency signals are added to the input, the line will output “1 ”Or“ 0. ”The frequency comparator shown in Figure 1 uses only three circuits: two CH4024 (seven binary addition counters for frequency division) and one CO39 (four two-input NOR gates). f_ ?? and f_R represent the input frequency and the reference frequency (of course, the exchange between the two, but the output polarity is reversed.) Because the two divider connection is exactly the same, so the count