某型探空火箭测发控系统高精度时钟的设计

Design of High Precision Clock for the Test-launching Control System of An Sounding Rocket

高精度时钟在某型探空火箭测发控系统中发挥着关键作用。提出了一种通过对PC/104嵌入式计算机板载8254定时/计数器重新编程来实现DOS操作系统下高精度时钟的方法,通过重新设定8254定时器0通道的计数值提高输出频率,通过高精度信号发生器对输出频率进行校准消除计数值引入的截断误差。试验结果表明该方法能够使PC/104计算机实现高精度时钟,确保测发控系统的各项测试精度达到技术要求。

High precision clock plays a key role in the test-launching control system of an sounding rocket.This paper presents a method to achieve the high precision clock in DOS through reprograming the 8254 timer/counter of the PC/104 embeded computer.The method increases the output frequency of the 8254 timer through resetting the count value of the channel 0,eliminates the truncation error introduced by the count value through using the high precision signal generator to calibrate the output frequency.Experimental results show that the proposed method can enable the PC/104 computer to achieve the high precision clock very well,and enable every test accuracy of the testlaunching control system to meet the technical requirements.