共查询到19条相似文献,搜索用时 125 毫秒
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高精度数据采集在压力测控系统中的应用 总被引:2,自引:0,他引:2
基于Window98平台,利用PC-7423A/D转换卡对压力测控系统中的压力信号进行采集,并通过几种定时方法的比较,选用多媒体定时器实现了对压力数据的定时获取。同时,采用数字滤波、自适应校正算法进一步提高了采集精度。最后,给出了用VC 开发的程序实例。 相似文献
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Win9X下定时器在水轮机振动摆度测试系统中的应用 总被引:3,自引:0,他引:3
在Windows操作系统下各种定时方式各有特点,而定时精度是衡量定时性能的一个重要指标,因此,很有必要定量的计算出水轮机振摆测试系统中定量器的定时精度。本文从定时器定时原理和工作流程入手,通过计算、分析和测试,定量的给出各种定时器的定时精度,并以一个具体工程实例说明定时器的使用。实验的结果证明,这种定量计算结果具有较高的精度和可信度。 相似文献
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《纳米技术与精密工程》2016,(3)
传统的叶尖定时信号处理方法在叶尖间隙改变的情况下定时值会发生变化,产生测量误差.本文提出一种提高光纤式叶尖定时系统定时精度的信号处理方法,采用同时分析脉冲信号上升沿与脉冲宽度的方法提高叶尖定时精度;研究分析了该方法的模型,并对该方法进行了实验验证.结果表明,在旋转叶片顶端前后沿切线基本平行的情况下,该方法可以有效减少叶尖间隙对叶片到达时刻测量的影响,提高了叶尖定时系统的精度. 相似文献
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1 测量方法 依据JJG909-1996《滚筒式车速表检验台》检定规程检定时,首先测量车速台滚筒的直径,将汽车驱动轮安置在车速台滚筒上,由汽车驱动车速台滚筒稳步加速,在车速台示值分别为30km/h、40km/h、60km/h时用转速表测量实际转速,每点测量6次,取平均值,并计算各点的相对示值误差。 相似文献
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基于PCI总线的高速实时数据采集在工业测控领域应用日趋广泛.通过对VB程序中的Timer控件计时、多媒体定时器函数计时、高性能频率函数法计时的对比实验,得到了几种不同计时方法的计时精度和重复性等实验对比数据.所编写程序数据采样频率最高可达11 kHz,并分析了不同计时方法的特性与应用场合,从而为进一步提高针对不同测量对象的计时控制精度,提供了一定科学的参考依据和方法. 相似文献
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为了评定胶鞋、运动鞋外底留痕程度,按照GB/T24129-2009《胶鞋、运动鞋外底不留痕试验方法》要求,研制了胶鞋、运动鞋外底不留痕试验机,本文介绍了该试验机的设计指标、基本结构、用途和测量方法。结果表明,该试验机能满足GB/T24129-2009《胶鞋、运动鞋外底不留痕试验方法》标准的要求,可广泛用于制鞋行业及检测机构,具有较大的推广价值。 相似文献
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首先阐述Windows系统环境下的消息处理机制;然后对Windows下几种常用精确定时器进行比较;最后设计一种基于多线程技术的高精度定时器。通过实际测试,验证了该定时器的高精度性能,很好地实现了以毫秒级定时的通信任务。 相似文献
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Saranovac L. Vasiljevic D.M. 《IEEE transactions on instrumentation and measurement》1994,43(6):943-945
The clock generation by software and by controller timer/counters is considered. The most complex case (when the controller has other tasks besides clock production) is resolved by the adaptable time delay compensation method. This method prevents the jitter which originates due to a different moment of interrupt request acceptance, and thus gives the same level of output clock jitter as for the microcontroller crystal oscillator (150 ps-standard deviation) 相似文献
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Countdown timers display the time left on the current signal, which makes drivers be more ready to react to the phase change. However, previous related studies have rarely explored the effects of countdown timer on driver’s brake perception-reaction time (BPRT) to yellow light. The goal of this study was therefore to characterize and model driver’s BPRT to yellow signal at signalized intersections with and without countdown timer. BPRT data for “first-to-stop” vehicles after yellow onset within the transitional zone were collected through on-site observation at six signalized intersections in Harbin, China. Statistical analysis showed that the observed 15th, 50th, and 85th percentile BPRTs without countdown timer were 0.52, 0.84, and 1.26 s, respectively. The observed 15th, 50th, and 85th percentile BPRTs with countdown timer were 0.32, 1.20, and 2.52 s, respectively. Log-logistic distribution appeared to best fit the BPRT without countdown timer, while Weibull distribution seemed to best fit the BPRT with countdown timer. After that, a Log-logistic accelerated failure time (AFT) duration model was developed to model driver’s BPRT without countdown timer, whereas a Weibull AFT duration model was established to model driver’s BPRT with countdown timer. Three significant factors affecting the BPRT identified in both AFT models included yellow-onset distance from the stop line, yellow-onset approach speed, and deceleration rate. No matter whether the presence of countdown timer or not, BPRT increased as yellow-onset distance to the stop line or deceleration rate increased, but decreased as yellow-onset speed increased. The impairment of driver’s BPRT due to countdown timer appeared to increase with yellow-onset distance to the stop line or deceleration rate, but decrease with yellow-onset speed. An increase in driver’s BPRT because of countdown timer may induce risky driving behaviors (i.e., stop abruptly, or even violate traffic signal), revealing a weakness of countdown timer in traffic safety aspect. 相似文献