46 results about "Allan variance" patented technology

A measuring device includes a pair of sensors, an actuator, a noise extraction unit and a low frequency noise (LFN) estimator. The sensors each generate with sample time Ts a sense signal indicating a value of a component of a vectorial physical quantity. The sensors have an Allan variance curve with a minimum value for a first integration time T1. The curve has a first and second tangent line being tangent at integration time 0, and integration time T1 respectively. The tangent lines intersect each other at an intersection point for a second integration time T2. The estimator having an effective integration time Teff determined by, Ts, T1 and T2, generates an estimated noise signal indicative for the estimated value of the noise component from the difference signal and from information about the relative rotation between the sensors.

The invention provides a DMTD measuring method and measuring system. According to the DMTD measuring method and measuring system, an uninterrupted common source signal is selected, two counters are used for acquiring the time counting values of the common source signal respectively in real time, when the rising edges of reference signals and the rising edges of detected signals come respectively, the time counting values of the current two counters are acquired respectively, the number of the rising edges of the reference signals and the number of the rising edges of the detected signals align at each other, the two time counting values corresponding to the aligning numbers are subtracted to obtain an accurate time difference value, and other frequency differences, phase differences, Allan variances and the like can be calculated according to the accurate time difference value. The common source signal mode is used, the problem that a traditional exclusive-OR gate mode can not conduct accurate measurement in times of edge overlapping or when two edge time differences are smaller than hardware response time is solved, and the cycle fuzzy phenomenon which commonly exists in the DMTD measuring process is avoided. In brief, the DMTD measuring method and measuring system can achieve quick, accurate, real-time and unlimited measuring with low cost.

A random error characteristic analysis method of optical fiber current transformer based on total variance, the method first collects the current signal of optical fiber current transformer through serial output, and obtains the observation data; Carry out zero-mean, trend item and standardization processing; test the stationarity, periodicity and normality of the processed data to obtain a stable, normal, and zero-mean data sequence; use the total variance method to perform variance processing on the data sequence; finally The logarithmic curve fitting of the total variance and the correlation time (τ) is carried out by using the square sum of the variance of the random error source, and five random error coefficients in the current information of the optical fiber current transformer are extracted. The invention can analyze the random error characteristics of the optical fiber current transformer more accurately, effectively solve the shortcoming of the traditional Allan variance method that the estimated value fluctuates violently, and provide guidance for the performance design of the optical fiber current transformer and compensation of random errors.