Design of high precision digital frequency meter

Two important features of electrical signals in time-domain are frequency and cycle, the measurement of which is an important way to understand signals. Digital frequency meter, closely relating to the measuring scheme of many electric parameters, has been widely applied to electronic experiments. The design and preparation method of a self made frequency meter with high precision is introduced. STC89C52 MCU is the core of the whole design, through which the counting, display, frequency division ratio and automatic range switching of the signals to be measured are controlled. The present design can achieve automatic display of counting, automatic range switching and measuring results. The measured results show that the maximum error rates of this frequency meter in three ranges are less than 0.1%, indicating a relatively high precision.