Design And Implementation Of Data Acquisition Based On Multi-thread Mechanism

With the development and progress of society, data collection system has been widely applied in industrial testing. At present, the output frequency of some AT-cut crystals will present frequency hopping effect at some specific temperature points. The crystal oscillator that made of frequency hopping crystal also has same characteristic of producing frequency hopping effect at some specific temperature points. This crystal oscillator output frequency violent hopping as temperature changing, which may cause serious issues, for example, the clock of communication system looses lock, and communication is exceptional while measurement error increases. To eliminate these failures of crystal oscillation, frequency data collection of crystal oscillator must be collected continuously and densely in the whole operating temperature range.This thesis is designed for data collection system of one company’s AT-cut crystal oscillator(about) high and low temperature testing. In contrast to traditional single-channel and low-speed data collection system, this thesis uses Pcomm serial port control pack to carry out serial communication. It adopts multi-threading mechanism to let the human-computer interaction of front end part, processing part and serial operation background part into parallel process. It also lets time-consuming I/O operation running backstage and it is quite effective to improve the responsiveness of the program in the condition of large amount of data communication. It is very successful to deal with multiple channels operating at the same time or a serial port simultaneously operating reading and writing, which can improve the program responsiveness time and resource utilization. This research also uses the method of piecewise linear interpolation approximating cubic curve to realize the crystal oscillator frequency hopping testing. The algorithm has the proproties of simple operating, fast testing, credibility judgment and high efficient testing, which is specially adapted in the testing of crystal oscillator frequency hopping related performance function in mass production processing of crystal oscillators. Experiment results show that the data collection system in the industrial field can work well, and it can meet the requirement of production.