使用单片机测频的四种方法分析——兼谈等精度测频法的实现

本文论述了使用单片机测频的四种方法,即直接计数法、周期测频法、混合测频法和等精度测频法。通过误差分析指出,直接计数法适于高频测量,周期测频法适于低频测量。在此基础上,提出具有通频带测频性质的混合测频法,并给出其测频最大相对误差和最大误差频率点的表达式。关于等精度测频法,提出利用软件查询实现同步的方法。并论证其测频精度可达10~(-6)

ANALYSIS OF FOUR METHODS ABOUT FREQUENCY MEASUR-MENT BY USING SINGLE-CHIP MIRCOMPUTER - WITH THE REALIZATION OF EQUAL ACCURACY METHOD ATTACHED

Four method are discussed about frequency measurment by using single - chip microcomputer. i. e. direct count method, period method, compound method and equal accuracy method. Through an error analysis.it is concluded that direct count method is suitable for the measurment of high frequency and period method for the measurment of low frequency. On the basis of the two methods.this paper proposes the compound method which has wide band character and derived the expressions of maximum relative error and maximum error point. As for the equal accuracy method .the way of software inquest is suggested in order to execute synchronization. It is proved that its accuracv can reach 10-6.