频率计

There are many noise sources in measuring the seismometer transfer function, the main noise sources are investigated. The method of cross-special analysis is presented, flow process diagram of computing is given, the algorithms are discussed in detail, such as low-pass digital filter, computing of seismometer transfer function initial values, time domain convolution, bilinear transformation, estimation of power spectrum and cross-spectrum, window functions and preprocessing of measuring data etc.

在地震计传递函数测试过程中的存在多中噪声，本文分析了主要的噪声来源；介绍了用互谱分析方法测试地震计频率特性的基本原理和方法；给出采用该方法确定地震计传递函数的算法流程图；并对计算过程中采用的低通滤波器、地震计传递函数的初值确定方法、卷积运算方法、自谱和互谱估计、采用的窗函数和测试数据的预处理进行了详细讨论。

This dissertation introduces the whole scheme、the hardware electro circuit design and software design, the result of experiment on salinometer is preferred at the end of the dissertation. Salinometer is base on SOPC technology, and use digital technology to design circuit: the excitation source for balance bridge is generated by digital method, its shape、amplitude and frequency can be control by digital signal, the standard branch of bridge is composed of three digital-analog-conversion, and uses the method of successive approximation to regulate the balance of bridge.

盐度计以SOPC技术为基础，通过数字化方式设计测量电路：电桥的激励源由数字化方式产生，激励源的波形、幅值和频率等可由数字量控制；平衡电桥标准支路由3个数模转换器组合实现，测量时以逐次逼近的方式调整电桥的平衡度；检测电桥平衡度的高灵敏度数字检流计同样以数字化方式设计，它的增益由程序控制，将电桥的输出电压数字化，以软件判断电桥平衡度。

Surveying several processes of rainfall, using the automatic hydrocone type ombrometer, analyzing the rainfall character in Dalian, drawing the frequency curve, especially, analyzing the time character of the storm, finding the time character of the storm, moreover, and the rainfall pattern is concerned.

利用安置在大连理工大学校园内的虹吸式自计雨量计，监测了数十场降雨过程，分析了大连市降雨的特点，计算并绘制出频率曲线，尤其对造成危害性较强的暴雨进行了时间特性的分析，结果得出了大连市暴雨的年、月、日以及短历时的时间特性，同时对雨型特点也进行了初步的分析。

High precision of data acquisition of accelerometers signal is achieved with V/F convertors.V/F convertors convert accelerometers analog signal into impulse which is transmitted to FPGA and converted digital signal.

为保证其高精度，采用了基于电压-频率转换的数据采集单元来完成加速度计信号的数字化。V/F转换器将加速度计输出的模拟信号转换为脉冲量，FPGA采集脉冲量并转换得到自标定模型所需数字量。

The third series of products are vibrating-wire sensors and 6 sets of testing instruments, including TX soil-pressure gauge, GX reinforcement forcemeter, FX counterforce gauge, SX pore pressure gauge, BX strain gauge, XX concrete stress gauge, MX rope dynamometer, vibrating-wire frequency meter, declinator, water-level meter and settlement meter, all of which are used for geotechnical engineering tests.

第三大系列为各类钢弦式传感器，仪器检测试验设备6套。产品主营有TX型土压力计、GX型钢筋测力计、FX型反力计、SX型孔隙水压力计、BX型应变计、XX混凝土应力计、MX锚索测力计、振弦式频率仪、测斜仪、水位仪、沉降仪、系列用于各类土工检测。

For the FA, the results indicated that the VPD calculation using mean of 24 hourly temperature values as saturation vapor pressure, and wet-bulb depression as actual vapor pressure yielded the lowest error, the least range, and the most frequency with the highest WI. These outcomes were as well as the SIA with the lowest EMSE, R^2 higher than 0.99 and the highest CE.

分析结果显示，以频率分析法而言，各地农业气候分区均呈现，VPD计算式以24个时温度日平均为饱和蒸汽压力，与湿球下陷量为实际蒸汽压力，具误差最少、全距最小、出现频率最多及最高权重指数，性能表现最佳，这样的结果，对照统计指标法之检测评估，同样具最低RMSE、R^2值0.99以上及最大CE，性能表现优於其他所有VPD计算式，两者，结果一致。

This experiment counts based on the direct digital frequencysynthesis the basic principle, fully II and hardware LT - IV testedthe box using ALtera Corporation's FPGA chip FLEX10 in softwareMaxplus in the platform to complete the DDS system design, hasdesigned a frequency and the phase may control has the sine and thecosine output direct numeral frequency synthesizer, was allowedto control and to observe the profile through the downloading boardand the Oscilloscope , completed in the enhancement request hascontrolled the frequency and the phase through the downloading boardon pressed key, as well as many kinds of profiles, includingsquare-wave, saw-tooth wave, triangle wave and cosine wave choiceoutput, In addition on digital tube dynamic demonstration productionprofile frequency, and produces the tbl document from the simulationprofile, simultaneously draws the profile using the matlab higherorder language.

帮忙翻译一下，谢谢本实验基于直接数字频率合成计的基本原理，充分利用ALtera公司的FPGA芯片FLEX10在软件MaxplusⅡ和硬件LT—IV实验箱的平台上完成了DDS系统的设计，设计了一个频率和相位均可控制的具有正弦和余弦输出的直接数字频率合成器，通过下载板和示波器可以控制和观察波形，在提高要求中完成了通过下载板上的按键来控制频率和相位，以及多种波形，包括方波、锯齿波、三角波和余弦波的选择输出，此外在数码管上动态显示生成的波形频率，并且从仿真波形中生成tbl文件，同时利用matlab高级语言画出波形。

This experiment counts based on the direct digital oscilloscope frequencysynthesis the basic principle, fully II and hardware LT - IV testedthe box using ALtera Corporation's FPGA chip FLEX10 in softwareMaxplus in the platform to complete the DDS system design, hasdesigned a frequency and the phase may control has the sine and thecosine output direct numeral frequency synthesizer, was allowedto control and to observe the profile through the downloading boardand the oscilloscope, completed in the enhancement request hascontrolled the frequency and the phase through the downloading boardon pressed key, as well as many kinds of profiles, includingsquare-wave, saw-tooth wave, triangle wave and cosine wave choiceoutput, In addition on digital oscilloscope tube dynamic demonstration productionprofile frequency, and produces the tbl document from the simulationprofile, simultaneously draws the profile using the matlab higherorder language.

帮忙翻译一下，谢谢本实验基于直接数字频率合成计的基本原理，充分利用ALtera公司的FPGA芯片FLEX10在软件MaxplusⅡ和硬件LT—IV实验箱的平台上完成了DDS系统的设计，设计了一个频率和相位均可控制的具有正弦和余弦输出的直接数字频率合成器，通过下载板和示波器可以控制和观察波形，在提高要求中完成了通过下载板上的按键来控制频率和相位，以及多种波形，包括方波、锯齿波、三角波和余弦波的选择输出，此外在数码管上动态显示生成的波形频率，并且从仿真波形中生成tbl文件，同时利用matlab高级语言画出波形。

To complete the DDS system design, hasdesigned a frequency and the phase may control has the sine and thecosine output direct numeral frequency synthesizer, was allowedto control and to observe the profile through the downloading boardand the oscilloscope, completed in the enhancement request hascontrolled the frequency and the phase through the downloading boardon pressed key, as well as many kinds of profiles, includingsquare-wave, saw-tooth wave, triangle wave and cosine wave choiceoutput, In addition on digital tube dynamic demonstration productionprofile frequency, and produces the tbl document from the simulationprofile, simultaneously draws the profile using the matlab higherorder language.

本实验基于直接数字频率合成计的基本原理，充分利用ALtera公司的FPGA芯片FLEX10在软件MaxplusⅡ和硬件LT—IV实验箱的平台上完成了DDS系统的设计，设计了一个频率和相位均可控制的具有正弦和余弦输出的直接数字频率合成器，通过下载板和示波器可以控制和观察波形，在提高要求中完成了通过下载板上的按键来控制频率和相位，以及多种波形，包括方波、锯齿波、三角波和余弦波的选择输出，此外在数码管上动态显示生成的波形频率，并且从仿真波形中生成tbl文件，同时利用matlab高级语言画出波形。

This experiment counts based on the direct digital frequencysynthesis the basic principle, fully II and hardware LT - IV testedthe box using ALtera Corporation's FPGA chip FLEX10 in softwareMaxplus in the platform to complete the DDS system design, hasdesigned a frequency and the phase may control has the sine and thecosine output direct numeral frequency synthesizer, was allowedto control and to observe the profile through the downloading boardand the oscilloscope, completed in the enhancement request hascontrolled the frequency and the phase through the downloading boardon pressed key, as well as many kinds of profiles, includingsquare-wave, saw-tooth wave, triangle wave and cosine wave choiceoutput, In addition on digital tube dynamic demonstration productionprofile frequency, and produces the tbl document from the simulationprofile, simultaneously draws the profile using the matlab higherorder language.

涂层测厚仪-帮忙翻译一下，谢谢涂层测厚仪-帮忙翻译一下，谢谢帮忙翻译一下，谢谢本实验基于直接数字频率合成计的基本原理，充分利用ALtera公司的FPGA芯片FLEX10在软件MaxplusⅡ和硬件LT—IV实验箱的平台上完成了DDS系统的设计，设计了一个频率和相位均可控制的具有正弦和余弦输出的直接数字频率合成器，通过下载板和示波器可以控制和观察波形，在提高要求中完成了通过下载板上的按键来控制频率和相位，以及多种波形，包括方波、锯齿波、三角波和余弦波的选择输出，此外在数码管上动态显示生成的波形频率，并且从仿真波形中生成tbl文件，同时利用matlab高级语言画出波形。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。