In the field of electronic technology, frequency is the most basic parameter. As a basic measuring instrument, the frequency meter is widely used for its high accuracy, fast speed, simple operation and digital display. Many physical quantities, such as temperature, pressure, flow, liquid level, pH, vibration, displacement, velocity, etc., are converted into signal frequency through transducers.

In particular, the combination of frequency meter and microprocessor can realize the multi-function, program control and intellectualization of measuring instruments. With the development of modern science and technology, all kinds of measuring instruments, control equipment and real-time monitoring system based on digital frequency meter have been applied to various aspects of international people's livelihood.

In the field of electronic measurement, frequency is an important parameter. It is often used as the basic parameter and reference value of computation. With the continuous development of computer network and Electronic Science and technology, the measurement of frequency is getting higher and higher. At this time, a high-precision frequency meter is particularly important.

The basic principle of digital frequency meter is to use a frequency source with high frequency stability as the reference clock, and to measure the frequency of other signals.

The SYN5636 type digital frequency meter is used as the advanced domestic frequency meter. Because of its complete functions, better performance indicators, high accuracy and sensitivity, wide measuring range, it has won a good reputation. It is especially suitable for time and frequency measurement in the fields of research and Metrology such as aerospace, missiles, weapons and other fields such as time measurement and crystal oscillator, electronic components and so on.

The SYN5636 type general counter has the "multiple parallel counting method": Based on multi-channel parallel processing capability, fast computation speed, low cost and high integration FPGA, it uses multiplex different frequency reference signals to count; absolute error can only be 1, and the highest accuracy count result is selected. When implemented, a high-speed comparator module is built by using a wideband amplifier and a high-speed comparator. The FPGA is used as the frequency measuring module. The control module is composed of single chip microcomputer, LCD display screen and keyboard, and the Verilog parallel programming is used to realize the "multi channel parallel counting method".

The gate circuit is used to control the counting time, consisting of a NAND gate. One end of the NAND gate is supplied by the time base pulse of the time base circuit, and the other end is input from the measured signal after being reshaped. The working principle of the circuit is that the time pulse provided by the time base circuit is used as the gating signal. When the gating signal is high, the gate is opened, and the pulse signal after shaping is passed through the gate to the frequency divider circuit. When the gating signal is low, the gate is closed, and the pulse signal is forbidden.

The copyright of this article belongs to Xi'an in all respects, respecting originality, strictly prohibit manuscript, unauthorized, no reprint, copyright, infringement must be investigated!