集成定时器系统在医疗设备中的应用

目的:通过对集成定时器系统的研究,及其在医学工程领域中的一些应用,阐述集成定时器系统的优越性,进而体现其在未来领域中的应用价值。方法:以555时基集成电路定时器为核心芯片,外加电阻、电容可以组成性能稳定而精确的多谐振荡器、单稳态触发电路及施密特触发器等电路,来驱动负载等电器件工作。结果:以555时基集成电路为核心的集成定时器,运行稳定且精度较高,电源适用范围宽且耗能低。结论:基于集成定时器系统的延时电路结构简单,具有成本低、精度高等优点,其将在科技、军事及医疗等领域有更加广泛的应用前景。

Effect of chip rate on the ranging accuracy in a regenerative pseudo-noise ranging system

The ranging accuracy of a pseudo-noise ranging system is mainly decided by range jitter and time delay discrimination. Many factors can affect the ranging accuracy, one of which is the chip rate. In digital signal processing, the time delay discrimination and autocorrelation function of sampled ranging sequences of different chip rates are very different. An approximation simulation model is established according to an in-phase quadrature (I/Q) correlator which is used to evaluate the time delay. Simulation results of the range jitter and time delay discrimination show that the chip rate which provides a non-integer sample-to-chip rate ratio can achieve a higher ranging accuracy, and some test results validate the simulation model. In some design missions, the simulation results may help to select an optimum sample-to-chip rate ratio to satisfy the design requirement on the ranging accuracy.