期刊论文

Principle and realization of frequency measuring with countingdown method

中文

武汉轻工大学学报

2095-7386

2014

3

67-69+83

10.3969/j.issn.2095-7386.2014.03.018

本校为第一机构

从雷达发射机耦合出来的发射脉冲信号经下变频、滤波后由比较器转换成中频方波信号,倒计数测频电路用该方波信号的Nx个周期形成计数区间,在此计数区间内使用F161高速计数器对100 MHz的标准方波进行计数,单片机根据计数结果计算出中频方波信号的频率和发射频率。该电路在雷达发射脉冲持续期间对其发射频率进行实时的快速测量,已成功用于某型米波警戒雷达的自动频率控制系统中。

The intermediate frequency signal , which is generated by down conversion of radar transmission pulse , is settled as square wave through the signal processing circuit;in N cycle of the unknown square wave of this frequen-cy, the frequency measurement circuit with counting down method uses the counter and the time -sequence control circuit consisting of TTL integrated circuit , such as F161 and LS221 , to count the standard pulse exported by ho-mothermal crystal with high stability and then load the result in single chip in order to obtain the frequency measur-ing result .This frequency measur...