采样误差

People are required to know and analyze the operating axes of rotary kiln in time in practice, in order to adjust and maintenance it in reason. So The Great Wall Aluminum Corporation of China bankrolled for studying the microcomputer real-time monitoring system of large-scale rotary kiln and commissioned Central South University to develop it.Based on analyzing and comparing the status quo of the monitoring system of rotary kiln, this paper brings forward a new method of monitoring the operating status of rotary kiln. It analyses the system-error and the configuration and demonstrate the feasibility in detail. In the design of hardware configuration it analyzes the principle and speciality of the tailor-made eddy current transducer and PCI-1713 analog input card and the multilevel supervisory network.

本论文首先在分析和比较同内外回转窑检测系统现状的基础上，首次提出了新的回转窑运行状态检测方法，并从系统误差及可行性角度进行了详细的分析和论证；其次，在监测系统硬件结构设计中，详细地分析了多级管理网络的实现，PCI-1713双缓冲区高速数据采集装置的原理、特点、工作过程，以及针对该系统恶劣的工作环境、特定性能要求而设计的特制电涡流传感器的原理、波形特性及性能特点，及为了减小非线性误差而采用计算机软件进行多段线性插补方法实现误差补偿；另外，在系统软件设计中，详细地分析了高速数据采样软件、智能信号处理软件、系统监测软件的实现，分析了采用模糊自适应滤波方法有效地滤除本系统恶劣环境下的各种干扰因素，并简要地介绍了系统分析软件的功能。

Error analysis of digital instruments on their characteristic parts including sample/holder circuit error and analogue/digital convector error was reviewed in this paper. With the help of some examples and data tables, error origins and the synthetic method were discussed.

评价了数显仪特征部分误差分析方法，包括：采样／保持电路、模数转换单元的误差，并通过典型例子和列表数据分析了多种误差源及其综合计算方法。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

By means of the discrete frequency spectrum, the frequency spectrum leakage s of the conventional DFT and the DFT with a Hanning window are comparatively analyzed in this paper.

利用离散频谱详细对比分析了DFT的频谱泄漏和加汉宁窗DFT的频谱泄漏现象，讨论了用异步顺序采样值计算电量产生误差的原因，提出了利用异步顺序采样值精确计算电量的方法，实现了畸变电量的精确测量。

Based on this formula, the effects on the measurent result caused by synchronizing error, sampling number, starting sampling point under arbitary irregular wave condition can be clearly analysed.

根据这一公式，可在任意畸变波形条件下分析由同步误差、采样点数、采样起点等对测量结果的影响。

Sampling frequency is also deduced oncondition that algorithm error has little effect on the dielectric loss angle measurement.

推导了在基于DFT的自适应整周期采样算法误差对介质损耗角测量影响不大条件下的采样频率，并进行了数值仿真。

The instrument simultaneously sample for three phase voltage and current. Rotary photoelectric coding switch and LCD are used for human-computer interaction. it makes the interface compact and efficient. Utilizing the function of positive and negative edge trigger of the programmable counter array unit in MPU, signal zero-cross is captured for the phase detected based on double way. The software synchronism sampling method based on real-time parameter self-optimizing minishes period truncation error, and the measurement accuracy is improved. The digitization power measure imports traditional two-unit and three-unit methods and expands application range of the instrument. The capacity is discriminated by soft ware table-look-up on the load loss. The value of a quantity is converted to the value when reference temperature (75 ℃) from test temperature.

该仪器具有以下特点：仪器对三相电压电流同时采样；基于旋转式光电编码器和液晶显示屏的人机交互界面简洁而高效；可编程计数器阵列PCA"捕获"信号的过零点用于双向过零平均鉴相，得到准确的相位差和周期；基于实时参数自寻优的软件同步采样，有效地减小了周期截断误差，提高了测量准确度；数字化功率测量引入了传统的二表法和三表法，扩展了仪器的使用范围；实际容量根据负载损耗用软件查表的方法来判别；测量值已从试验温度折算到了参考温度(75℃)时的值。

According to the character of power system, this paper analyzes the digital spectral structure and representation of a sampled periodic signal and discusses the influence to the A.

但是，这种采样技术由于时基不准确，造成的各路A/D之间存在着不容忽视的延时误差，因此必然存在着非均匀采样现象。

Harvested area error of yield point is one of the main reasons to bring yield error in yield data collected by yield monitoring system.

采样周期内实际收割面积计算误差造成的产量数据误差是联合收割机计产数据中的一种常见误差。

Based on the CMMB system signal model, symbol timing synchronization error, sampling clock offset error and carrier frequency offset error are analyzed carefully.

在建立CMMB系统信号模型基础上，分析了符号定时同步误差，采样钟偏移误差，载波频偏误差对CMMB系统性能的影响。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。