数字输出控制

Through analyzing the traditional implement method,the phase introduced by the quantization error of the frequency control word is put forward.

介绍了一种对基于DDS的数字本振的改进，分析了传统的数控振荡器的实现方法，指出其中由于频率控制字的量化误差带来的振荡器输出相位误差。

The former is the core of hardware, it is based on industrial control computer that expended with analog signal input board and digital signals input and output board.

其中工控机是自动化测试系统的硬件核心，在工控机内扩展了数据采集卡和数字量I/O卡，完成对电源输入、输出信号的采集和对系统的控制。

Utilize mathematical operation of the one-chip computer and control the function, combine the digital circuit of some scale of China, have realized the producing of variable frequency sinusoidal wave and the measurement of frequency , cycle , width of pulse to the signal ,etc.

利用单片机的数学运算和控制功能，结合部分中规模数字电路，实现了一些波形的输出，及对信号的频率、周期、脉冲宽度等的测量，使用单片机使整个系统具有极为灵活的可编程性，能方便地对系统进行功能扩展与改进。

Circuit system used varistor constitute the Wheatstone bridge to collect small changes in voltage, After amplification circuit amplified into A / D converter circuit, the input voltage digital signal after the conversion output AT89S52 conducted by the control and data processing and results in the LCD display.

系统电路采用压敏电阻构成惠斯登电桥来采集电压的微小变化，经过放大电路放大后送入A/D转换电路，对输入电压信号进行数字量的转换后输出，由AT89S52进行系统的控制和对数据的处理并将结果显示在液晶显示器上。

The digital frequency source this paper researched uses high integrated DDS chip AD9851 as frequency sources and signal mirac processors AT89C51 as system control center, it can output 10Hz-20MHz signal with high-precision and high stability frequency. The evenness of signal within the range of 10MHz is low to 0.1dB degree, and the smallest step is low to 10Hz frequency.

本课题研究的数字频率源采用高集成度DDS芯片AD9851作为频率源；以单片机AT89C51作为系统的控制中心，实现了10Hz～20MHz的高精度、高稳定度的频率输出。10MHz内信号幅度的平坦度为0.1dB、频率最小步进为10Hz。

The rotproof and wearable kinds of pressure transducers and transmitters are suitable for pressure measurement on various occations of chemical fibre, plastic, rubber and petrifaction . They can succeed in measuring and controlling pressure with our Series PW intelligent digital pressure gauges.

防腐耐磨型压力传感器及变送器使用于塑料、化纤、石化等各种特殊场合的压力测量，与我公司的PW系列智能数字压力表配套使用可实现压力的测量与控制，变送器系列采用24V直流供电，输出标准信号便于计算机采集。

In this system, the wavelength of the narrow-bandwidth optical source from the Fabry-Perot tunable filter and broadband source could be adjusted by the digital signal processor after the operating point is changed. Moreover, the influence of the factors such as the instability of the light source and the slowly unaccelerated aging of the system, can be eliminated or decreased by the auto-calibration method based on the software.

该系统利用数字信号处理器控制可调珐珀滤波器自动输出波长满足工作点要求的窄带光，同时还通过软件校准的办法消除了因光源的不稳定、系统老化等缓变因素引起的信号波动对测量结果的影响。

A7800 Features: 10 Mb s Manchester encoding decoding with receive clock recovery Patented digital phase locked loop decoder re- quires no precision external components Decodes Manchester data with up to g18 ns of jitter Loopback capability for diagnostics Externally selectable half or full step modes of opera- tion at transmit output Squelch circuits at the receive and collision inputs re- ject noise High voltage protection at transceiver interface (16V) TTL MOS compatible controller interface Connects directly to the transceiver cable A7800 Maximum Ratings: A7800 Pinout:· NPT IGBT technology · low saturation voltage · low switching losses · switching frequency up to 30 kHz · square RBSOA, no latch up · high short circuit capability · positive temperature coefficient for easy parallelling · MOS input, voltage controlled · ultra fast free wheeling diodes · solderable pins for PCB mounting · package with copper base plate

A7800特点： 10兆s曼彻斯特编码与接收时钟恢复专利解码数字锁相环解码器重新奎雷斯没有精确数据的外部元件曼彻斯特解码高达全部G18抖动纳秒环回功能用于诊断外部可选的一半或整步模式的歌剧和灰在传输和接收碰撞投入重新ject高噪音在收发器接口（16V的）马鞍山的TTL兼容控制器接口电压保护输出静噪电路直接连接到收发器的电缆 A7800最大额定值： A7800引脚说明：·不扩散核武器条约IGBT技术·低饱和电压·低开关损耗·开关频率可达30千赫·平方米RBSOA，没有锁定了高短路能力··正温度，便于parallelling·马鞍山消耗系数，电压控制·超高速免费·印刷电路板焊接的引脚安装·铜底板包续流二极管

Barker is synchronized code in digital communication. In this paper, design methods of barker 7 data transmitting card arc presented. The application background of Barker are introduced. The used methods of MCU 80C196KB and CPLD EPM7128SLC are set forth. Transmitting card is designed and implemented by using interface circuit and above-mentioned chips. The control process of barker 7 is introduced under PC parallel-port EPP mode. The partial design circuit is given, the cards is proved to achieve the generation and output of 7 Barker through practice. it can satisfy testing requirements of a certain Russian-made airborne product.

巴克码是数字通信中常用的信息同步码型；提出一种7位巴克码数据发送卡的设计方法：介绍了巴克码应用背景，阐述80C196KB单片机、EPM7128SLC可编程逻辑器件的使用方法，利用上述芯片和分立元件设计并实现7位巴克码数据发送卡；介绍了并口EEP模式下巴克码的控制过程，给出了巴克码数据发送卡部分设计电路，介绍了码型实现过程；通过实践证明了该发送卡能够实现7位巴克码的生成与输出，完全满足某型俄制机载产品测试要求。

Aiming to solve the shortcoming in the prior art that any on-line DCF dispersion compensation technology is not provided for long distance, and the nonlinear effect in the dispersion compensation technology is restrained, the invention provides the dispersion compensation method, which includes the steps that after a sending end implements electric pre-compensation treatment on a digital signal to be transmitted, a control electric/optical converter module outputs a distorted optical signal; after receiving the optical signal, a receiving end conducts a post compensation treatment after converting the optical signal into an electric signal, or converts the optical signal into the electric signal after implementing the post compensation treatment.

为了解决现有技术中长距离无在线DCF色散补偿技术的不足和抑制色散补偿技术中的非线性效应，本发明提供了一种色散补偿方法，包括发送端将待发射的数字信号进行电预补偿处理后，控制电/光转换模块输出畸变光信号，接收端收到光信号后，将光信号转换为电信号后进行后补偿处理，或将光信号进行后补偿处理后转换为电信号的步骤。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。