基于MSP430单片机的高精度数字频率计设计

High-precision digital frequency meter design based on MSP430 micro controller

在电路设计中,频率是一个常被使用的量,目前很多示波器也增加了测频功能,但市场上鲜有体积小、精度高的数字频率计。基于MSP430F425单片机,设计出了一款体积小且精度高的多功能数字频率计,可完成对信号频率、周期、脉宽、占空比的测量。整个系统主要由放大整形、数据处理、LCD显示三部分组成。在低频段,系统采用"周期法"测频,在高频段则采用"闸门法",测频相对误差低至0.006%。同时,为适应不同的应用场合,提出了一种测频精度可调的系统。

In circuit design, frequency is a commonly used quantity, so far in the market, there are many oscilloscopes with the frequency measurement function, but we can seldom see digital frequency meter in the market, Based on MSP430F425 micro controller, the design is devised with small volume, high precision and multi-function digital frequency meter, and it can be used in the measurement of signal frequency, period, pulse width, and duty cycle. The whole system mainly consists of voltage amplify and waveform shaping, data processing, and LCD display. At low frequency band, the system uses the ＂period method＂ frequency measurement, while at high frequency band, it uses the＂gate method＂, with which the relative frequency measurement error can be controlled below 0.006%. In order to adapt to different applications, we also proposed an adjustable frequency measurement accuracy system.