In the aspect of hardware design , the single - chip microcomputer " s minimum system is applied to design display device about keyboard operation and dac ( analog - to - digital converter ) which economizes large quantity of hardware resource 在系统的硬件设计方面，对于键盘显示和数-模转换dac ，采用单片机的非总线应用系统的最小系统，节约了大量的硬件资源。
In addition , some interface circuits , such as high - power d / a card , filter board , logic - process board and the feature of cvi programming language and windows programming are also introduced in detail with some chapters 后面章节详细介绍了系统的一些接口和控制电路，如大功率数模转换板、滤波器、控制逻辑处理器等等，以及cvi工业控制软件开发环境及windows编程等软件方面的内容。
The current in the dac ’ s output can drive the load , and the structure can save a buffer consisted of operational amplifier , so the structure can achieve high speed with no close - loop and feedback in this circuit 该10位分段式电流舵型数模转换器的输出端可直接用电流输出来驱动负载阻抗,省去运算放大器构成的输出缓冲,整个电路中没有形成闭环和反馈,因此这种电路结构可以达到很高的速度。
With the fast development of computer technology , digital processing technology and microelectronic technology , advantaged video systems are presented continually . this paper has given the basic design principle and architecture of high speed and low dissipation of dac 随着计算机技术、信号处理技术、微电子技术的快速发展,先进的电子视频系统不断涌现,进而推动了高速、低功耗数模转换器的不断发展。
This digital pattern generator composes of eight parts : interface circuit unit , dual - port sram unit , dsp unit , dac unit , expose / mark signal detection control unit , mark signal diction unit and final expose shape registers unit 本论文中的新型图形发生器由接口电路、双端口存储电路、数字信号处理电路、数模转换电路、曝光标记检测控制电路、标记检测电路、最终曝光数据寄存器单元和束闸控制电路构成。
In this thesis , the technology of analog to digital converter ( adc ) and digital to analog converter ( dac ) were reviewed in detail from the perspectives of the modern electronic technology applications , including principles , comparison of characteristics , main technical indicators and applications 摘要本文从现代电子技术应用角度出发，介绍模数和数模转换器的技术，包括工作原理、特性的对比、主要技术指标及发展应用。
The root cause of this is that before the constantly changing analog signals from thermocouples or resistance thermometers can be processed digitally , an analog - to - digital conversion process is necessary , often resulting in loss of overall accuracy and measurable time delays 它的起因是可能经常从热电偶或抵抗温度计改变的模拟信号，而需要处理数字信号,一个数模转换过程是必要的,经常造成全面准确性和测量时间延误的损失。
In the practical measurement , the designed card has acquired the data successfully and also completed the single - channel conversation of d / a . according to the analysis of the sampling signals , the design is proved to be a success and the performance meets the expectations 通过实际测试，该数据采集卡顺利完成了数据采集功能，并实现了单路数模转换，对采样结果的波形分析，验证了本次设计的合理正确性，达到了预期的设计效果。
The combination of cablemodem and hfc is a way to revamp the catv network to a hybrid videodata communications network . however , hfc uses sub - carrier fdm , which requires ad conversion before transmission . in that sense , the transmission quality will be compromised 虽然cablemodem与hfc配合，是将catv网改造成为视频、数据混合通信网的一种可能选择，但hfc采用副载波频分复用方式，必须进行数模转换才能传输，所以传输质量将受到影响。
Rapid development of data business , growing of packet network technology , and increasing of communication channel capacity , etc , bring this problem the answer : the next generation network will be base on the ip , and it will be to consist of network architecture which are diverse , synthetic and open such as speech sound , data , multimedia etc . the principle of voip ( voice over internet protocol ) is not complicated : at the sending end , sample the analogue speech sound signal , code and compress , then package and transmit it over the packet network 数据业务的快速发展、分组网络技术的成熟、数据网络通信信道容量的不断增加等给这个问题提供了答案：下一代网络将是基于ip的，下一代网络将是可以提供包括语音、数据和多媒体等各种业务的、综合的、开放的网络构架，而voip正是这个答案的具体体现。实现voip的原理并不复杂：将模拟的语音信号采样、编码并进行压缩，封装在数据网络的分组中进行传输，在接收端对数据进行解码、数模转换恢复成模拟信号即可。
