精密时频和数字化测量和处理中的边沿效应及其应用

Border effect and its application in precise time-frequency field and digitalized measurement

边沿效应,就是在进行如相位、频率、电压、以及被传感信号等量值测量时,因为装置的分辨率有限,会在测量目标附近形成一个模糊区。这常常是测量仪器发展的一种障碍。深入研究不同量值模糊区的边沿特性,发现利用边沿效应能够获得更好的处理结果,例如大幅度地提高测量精度、扩展测量的范围、取得更快的响应时间等。时频、尤其是相位处理的手段也同时是数字化技术进一步发展的基础。借助于“相位重合”的思路、高频时钟下A/D采样的“跳变沿”处数字转换值与实时模拟电压的拟合效应,边沿效应和等效相位处理思路的结合,在交流电压测量中利用8位A/D转换器能够得到与21位数字电压表一样的电压测量精度,同时又解决了传统的数字电压表无法精密测量高频电压的问题。反过来,这方面的成果用于数字化线性相位比对中,使得16位A/D转换器的数字化线性相位比对的分辨率(秒级)从-13量级进步到-14量级。时频测量具有所有物理量中的最高测量分辨率。把时频处理的原理、方法等通过相位概念的扩展并且结合边沿效应的应用移植到更广泛的数字化测量以及传感器应用中,具体在AD转换的数字/时刻、以及其变化率的跳变沿利用的处理等,能够解决广泛的测量和控制问题。例如,频标比对中的差拍周期法移植到更广泛的AD转换的数字测量中,通过时钟采样周期性地对于被测电压的相位步进,能够获得更高频率模拟量的准确波形变化参数以及其他信息。大幅度提高精度的同时也解决了特高频电压数字测量。

Border effect is a phenomenon that when a device measures quantities like phase,frequency,voltage,and other sensed signals,a fuzzy area will be formed near the measured quantity due to the limited resolution of the device.This is often a hindrance to the development of measuring instruments.Through in-depth research on the border characteristics of fuzzy areas with different magnitudes,it is found that better processing results can be obtained by using border effects,such as greatly improving the measurement precision,expanding the measurement range,and obtaining faster response time.The processing strategies in the time-frequency field,especially in the phase processing,are also the basis for the further development of digital technology.With the help of the idea of“phase coincidence”,the fitting effects of the digital conversion at the“hop edge”of A/D sampling under high-frequency clock and the real-time analog voltage,the combination of border effect and the equivalent phase processing idea,the 8-bit A/D converter can obtain the same voltage measurement precision as the 21-bit digital voltmeter.This at the same time solves the problem that the traditional digital voltmeter cannot precisely measure the high-frequency voltage.In turn,the results of this aspect are applied in the digital linear phase comparison,making the resolution of the digital linear phase comparison of 16-bit A/D converter improve from the order of-13 to-14.The measurements in the time-frequency field have the highest measurement resolution of all physical quantities.The principles and methods of time-frequency processing can be extended to a wider range of digital measurement and sensor applications through the expansion of the phase concept,combined with the application of border effects.It can solve a wide range of measurement and control problems by processing the digital moment of AD conversion and the jump border of its changing rate.For example,the beat period method in the frequency standard comparison is transplanted into the digital measurement of the wider AD conversion.The phase step of the measured voltage is periodically stepped by the clock sampling,and the accurate waveform variation and other information of the higher frequency analog quantities can be obtained.While greatly improving the precision,it also solves the problem of digital measurement of ultra-high frequency(UHF)voltage.