The Research Of A New Frequency Measure And Control System Based On DSP

With the quartz crystal's broader application in the field of electron, Home quartz crystal industry develops rapidly. While, highly precision frequency measure and control apparatuses used in producing process are depended on import basically and expensive, which contradicts with the increasing requirements for such apparatuses in home crystal manufacturing and restricts the development of home crystal industry mostly.This paper describes the research of a new frequency measure and control system, which can measure the crystal's variational frequency in the process of rubbing on line and can control automatically the rubbing thickness. Old imported apparatuses' control core are all 8 bit low-speed SCM, now, DSP (Digital Signal Processor) is adopted as core instead of SCM in this new system firstly and PLL is also adopted to make up of frequency-scanning part. TMS320F240 is a DSP CMOS chip in C2000 series. This chip can collect frequency respond signals, can produce frequency measure and control logical signals, can calculate wafer's resonance frequency and frequency difference, can enact and display frequency, and can process signals from keyboard. The PLL part, made of PD, Loop Filter, Voltage Control Oscillator, is the key circuit of the system to produce steady and continuous frequency scanning signal.This paper firstly introduces the basic knowledge of DSP CMOS chip, PLL and Programmable Logic Devices in the system whole frame design, then discusses the hardware design plan, work principles and application software design generally and by the numbers, and introduces some anti-jamming measures. In the end, one scheme is put forward to strengthen the system's anti-jamming ability, that is to use a DPLL CMOS chip instead of the existing PLL. It illustrates that well-pleasing effect can be gained by the control system.