Research On High Precision Frequency Measurement Method Base On The Vernier Method

In order to effectively improve the problem of low accuracy and big error of traditional frequency measurement, a kind of high precision frequency measurement scheme based on multi-period frequency division and double vernier measurement has been proposed in this paper. The system with FPGA as the platform constructs logic control and pulse counting module, meanwhile, NIOS Ⅱ processor is embedded FPGA chip as data processing controller, it mainly used for measuring the pulse signal of inertial components outputs the scope of0.1Hz-5MHz, and the data of measured results can be transferred to computer interface written by Visual C++6.0to display in real time.The paper is contrast to the traditional pulse signal frequency measurement method on the basis of the advantages and disadvantages, based on vernier method of frequency high precision measurement system is designed. According to the design demand, the whole frequency measuring system is divided into three parts, namely hardware platform design, NIOS Ⅱ soft core processor system software design and cpistatic machine application programming.Firstly, the paper introduces the frequency measuring system overall design ideas, secondly the system function structure and hardware design and software design are described in details. In hardware circuit design, Altera Corporation’s EP2C8Q208C8N is regard as platform, with SOPC Builder of Quartus Ⅱ software design NIOS Ⅱ soft core processor system, as the core controller of frequency measurement system, it fulfills the hardware each function module and data transmission interface design. Software design includes NIOS Ⅱ soft core processor system program design and epistatic machine application programming. The former makes use of C language gained Meter numerical through the PIO interface (parallel I/O port) and data processing, and sends the data of measurement to epistatic machine through the serial port to in NIOS Ⅱ9.0IDE integrated development environment. The latter designs epistatic machine application through the Visual C++6.0software platform in the Windows operating systems, it can send control command to lower computer and receive the measurement data from lower computer per second, meanwhile, process and display and save data, it achieves testing for pulse signal frequency of the inertial navigation component output in real time.Finally, hardware-software of frequency measurement system is debugged, the measurement data is analyzed.The test results show that this system can effectively measure inertial navigation component output pulse signal frequency and meet the design demand, meanwhile, it is easy to be improved and adjusted, all in all, this system works well and has practical value.