Research on digital frequency meter based on single chip microcomputer

Abstract

Frequency is one of the most basic technical indicators in the field of electronic technology. As a basic measuring instrument, digital frequency meter has been widely used for its high precision, fast speed and digital display. It is used to measure the frequency of signal waveforms. This paper introduces a digital frequency meter based on single chip microcomputer. The control adopts the STM32 series based on the ARM architecture. The frequency measurement range of the frequency meter is 0.1Hz to 10MHz. It is divided into high frequency and low frequency with 1KHz as the boundary. The frequency is measured by the period measurement method, and the pulse counting method is used to measure the frequency in the high frequency band. For low frequency bands, the resolution can reach 0.0001Hz, the error is less than 0.1%, and the duty cycle of square wave signals can be measured. The resolution of the high frequency band is 1Hz, and the error is less than 0.1%; there are three measurement gears of Hz, KHz, and MHz, and the gears are automatically switched during measurement and displayed on the display device. The digital frequency meter introduced in this paper consists of 4 modules, namely: signal amplification and shaping module, MCU main control module, display output module, and power supply module.