Frequency is a basic parameter of electron technology field, but also a very important parameter. It is very closely related with many measurement scheme and measurement results of electricity parameter. So the Frequency measurement plays a more important role in science and technology research and actual application.
This frequency meter designs is based on the designing thought of the 51 series single-chip to achieve, it makes full use of self hardware resources AT89C52, forming a minimum hardware system, to measure the output frequency of different waveforms signals. The circuit demonstrates apart is built up by the circuit of HD7279A element and three-position digital tube. The waveform changing and shaping apart is based on the circuit of Schmidt trigger which made up of 555 Timer. The single-chip controlling program of the software apart is written by the C51. And adopt different way of measuring paragraph to promote the measurement accuracy, and display the measurement results on the LED.
Keywords: frequency meter, single-chip, HD7279A, Schmidt trigger