座谈主题:模数转换器（ADC）的基本原理
在线问答
[问：zpfar]	用8位单片机读12位ADC，精度会不会有影响？
[答： Wayne_Zhou]	No problem, you can interface with serial int. Or parallel, using buffer.	[2002-11-26 10:39:03]
[答：单词翻译]	serial :串行 parallel：并行 buffer：缓冲器.
[问：wylinder]	请问采样率和转换速度有和联系？
[答：Liao_ Wen_Shuai]	This relates to the architecture of the ADC. If it is SAR, pipeline or flash ADC, if sampling rate is high then the conversion speed is high. If it is sigma-delta ADC, then this will be decided by the internal structure of the ADC.	[2002-11-26 10:43:14]
[答：单词翻译]	sampling rate：采样速率 conversion speed ：转换速度
[问：ecnanjing _EBY7E]	对一飞行速度极快的物体进行速度测量， V=1000m/s,ADI的前放和ADC如何选择？
[答： Wayne_Zhou]	It depends on the sensor you used, and the resolution you need. Normally you need high speed amp and ADC, if you want to reach high accuracy.	[2002-11-26 10:44:13]
[答：单词翻译]	sensor：传感器  amp：放大器
[问： hanshang _007]	专家！在布线时，怎样布模拟地和数字地才能是干扰最小？
[答：Liao_Wen _Shuai]	To separate the interference from digital ground, you need to use one-point grounding technology. You can refer to materials from the following links: http://www.analog.com/technology/amplifiersLinear/ training/highspeed.html or http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html	[2002-11-26 10:45:53]
[答：单词翻译]	interference ：干扰
[问：hefeng]	我们都知道采样率和分辨率都会影响到AD/DA转换器的精度。 请问Analog Deviced公司的工程师，你们公司是怎么样提高 自己产品的精度，你们最好的产品精度能够做到什么程度？
[答： Eagle_Zhang]	We have many expert that have more than 10 years design experience. The best ADC:AD7738 24 bit 0.05 ~ 12.3K , AD7674:18 bit SAR @800k, AD7677: 16bit SAR @1MHz, AD6645: 14bit @ 105MHz, AD9430: 12bit @ 210MHz.	[2002-11-26 10:46:15]
[问：zhyh]	AD校准能否实现在线校准，或者出厂前校准？
[答： Charles_Lee]	This is dependent on the ADC vendor. Normally, it used on board calibration on your circuits.	[2002-11-26 10:49:45]
[答：单词翻译]	on board calibration：在电路板上校准
[问：zhyh]	What"s the different of the AD775X and CS54XX?Can I use AD775x instead of CS54XX?
[答： Mike_Byrne]	This question relates to our application specific products targeted at energy metering applications. Can you please contact harry.wu@analog.com regarding questions on these products.	[2002-11-26 10:50:26]
[答：单词翻译]	energy metering：能量测定
[问： Wuquanying]	传感器采集的微弱信号经运算放大器放大后输入A/D模数转换器时， 采用何种A/D比较好？
[答： Wayne_Zhou]	Basically it depends on the signal amplitude after amplifier, and the resolution you need. However, for small signal, suggest to use bridge, and you can use AD7730 for directly handling bridge signal. You can also refer to the materials on below link: http://www.analog.com/technology/amplifiersLinear/ training/sensorSignal.html	[2002-11-26 10:52:57]
[问：chen_pin]	可以根据你的经验，谈谈ADC在布电路板时，为了提高性噪比。需要注意哪些么？可能不同的片子，不太一样，可以谈谈一般的经验么？包括地屏蔽，通道之间串扰，电源旁路，布线长度，等等。谢谢！因为我以前做板子时，没有太多的注意。
[答： Eagle_Zhang]	1. Every 0.1uF decouple CAP as near as possible to VCC pin. 2. Good disperse. As far as possible to noise SDRAM, CPU. 3. A whole Ground layer, seperate Power square for different power. 4. Good match in input, 25~200 Ohm match resister in Data bus. 5. please refered to: High speed design techniques http://www.analog.com/technology/amplifiersLinear/ training/highspeed.html	[2002-11-26 10:53:52]
[答：单词翻译]	match resister：匹配电阻
[问：geyunfeng]	是否在A/D转换前均要进行有源低通滤波，如果我的采样频率是1440Hz，是否我的低通滤波的截至频率要在低于720Hz以下
[答：Charles_Lee]	Yes, normally case you can do it But you have to totally understand your signal bandwidth. If the signal BW is low enough, you can use the LPF with low cut-off frequency.	[2002-11-26 10:54:26]
[答：单词翻译]	signal bandwidth：信号带宽  LPF ：低通滤波器
[问： keyi.wu@ philips.com]	What causes DNL error?
[答：Cindy_ Bloomingdale]	DNL is the deviation of an actual code width from the ideal (in regards to the converter transfer function).  Device mismatches inside the A/D converter cause errors in the transfer function.	[2002-11-26 10:54:54]
[答：单词翻译]	code width :码宽 Device mismatches ：器件的不匹配  transfer function：传输函数.
[问： jeffreyxiao @21cn.com]	我们都知道在有ADC的IC设计中，Vref的设计尤其重要，请问Vref设计要注意一些什么？通常怎么解决？
[答：Liao_Wen _Shuai]	Normally, you sholuld select a reference part that can compatible with the precision of the ADC that will be used. So, please analyze the precision of the ADC and the noise first. You can get more information from the link below: http://www.analog.com/technology/amplifiersLinear /training/sensorSignal.html And sometimes you can use some technologies to screen the error of the reference.	[2002-11-26 10:55:03]
[问：cruos]	如果要扩展动态范围，是否可以采取小信号放大后再进行ADC量化，对于这个过程中的模拟电路有什么要求（例如时延和相移，以及失真等）？多片高速ADC的硬件实现上的布线原则是什么？怎样在实际中确保相互间产生最小的影响？高速ADC可能功耗比较大，对于散热的要求是什么？对工作环境的要求？
[答： Wayne_Zhou]	Yes, you can choose ADC with PGA, which means you can have different input range, then the dymanic range of ADC can be improved. For other actual design questions, below is a link to a good design guide of high speed ADC from ADI: http://www.analog.com/technology/amplifiersLinear/ training/highspeed.html	[2002-11-26 10:56:52]
[答：单词翻译]	dymanic range: 动态范围
[问： zhangw@ nstek.com.cn]	您好。我想请教：当采样率和采样速度发生冲突时，我应该怎样做？谢谢
[答： Eagle_Zhang]	Sorry I do not know what you mean. You can use under sampling if signal input frequency is great than ADC sample clock. For example, sample 70MHz IF with AD6644 (65MHz, 14bit) if the band width is only 5Mhz.	[2002-11-26 10:57:42]
[问：samire]	请较为详细介绍取样时钟波形对ADC性能的影响。谢谢！
[答：Liao_Wen _Shuai]	Normally, it will be better to use the clock with fast slew rate. This means square wave clock will be better than sinewave clock. You can refer to the link below for more information: http://www.analog.com/technology/amplifiersLinear/ training/highspeed.html Or, you can find this information from the datasheet, AD6644 for example.	[2002-11-26 10:57:55]
[答：单词翻译]	slew rate：转换速率.  square wave：方波  sinewave：正弦波
[问： fengzhaoqun]	我需要选择八通道的12bit同时采样的ADC，每道的采样频率大于150KSPS,请问ADI有什么产品可以推荐？
[答： Charles_Lee]	You can check AD7864 x 2 and AD7866 x 2.	[2002-11-26 10:58:05]
[问：zfzhan]	10位的ADC，做成采集卡，插在PC机上 有效位一般能达到多少？
[答： Charles_Lee]	It"s dependent on the ADC you choice, the power supply and the PCB layout. If the ADC"s INL/DNL and PCB power supply/ PCBlayout is good enough, you can achieve 10 bits resolution.	[2002-11-26 10:58:43]
[问：reinaci]	采样时钟的抖动对ADC的影响，满足要求的ADC性能应该提供什么样（对于抖动）的时钟？比如，8.192MHz采样1.4MHz中心频率、带宽200KHz，如果要求ADC（14Bit）输出65dB SNR的量化信号，对采样时钟的抖动有何要求呢？
[答： Wayne_Zhou]	Please refer to page 19 of this seminar.	[2002-11-26 10:59:05]
[问：hefeng]	在高速系统中，或者我的系统中对时延要求比较苛刻，双级ADC会不会造成延时方面的问题？
[答：Cindy_ Bloomingdale]	Pipeline ADC latency delays can vary from just a few clock cycles to more than 10 clock cycles, depending on the architecture of the ADC, the resolution, and the sample rate.  Most of our high speed converters today use a pipeline architecture because of the many benefits, including lower power dissipation.  A pipeline architecture requires fewer comparators which burn power.  Depending on the ADC requirements, the best type of ADC in a "real time" system is a SAR.	[2002-11-26 10:59:55]
[答：单词翻译]	latency delays：等待延时
[问：ecnanjing _EBY7E]	三种类型的ADC在实际使用中，如何兼容，DSP或MCU能否自动设别ADC的类型？
[答：Liao_Wen _Shuai]	I don"t which three type of ADC you are mentioned. We introduced four types of ADC in the seminar. DSP and MCU cannot identify the type of the ADC.	[2002-11-26 11:00:54]
[问：ljp]	ADC的转换速率如何影响ADC的性能？如失真和噪音？
[答： Charles_Lee]	Normal case, the higher speed you get will cause more THD and noise problem. The most obvious one is the ADC"s ENOB will reduce.	[2002-11-26 11:01:25]
[答：单词翻译]	THD：总失真
[问：samire]	时钟的占空比对转换速度，噪音性能有何影响？
[答： Wayne_Zhou]	For those ADC using only rising edge of falling edge, no problem. But it"s typically important for those ADC using both edge, it need half-half duty cycle.	[2002-11-26 11:01:26]
[答：单词翻译]	rising edge：上升沿  falling edge：下降沿 half-half duty cycle：50%占空比
[问：chen_pin]	您知道哪款ADC芯片可以实现4个通道同时采样，各通道采样率同时可达50K次/S（4个通道内部并行采保），具有16位数据精度，8位（或16位）并行接口。我以前使用MAX125/126，但是它的精度只有14位，而且温度误差有2位左右，也就是说最坏可能时 只有12位的精度。可能我问的太具体了，如果您知道，请给我建议一款型号。谢谢！
[答： Mike_Byrne]	The AD7865 offers a 14-bit, 4-channel simultaneous sampling ADC. For higher resolution, simultaneous sampling applications the AD7654 offers a 2-channel simultaneous sampling 16-bit A/D converter.	[2002-11-26 11:02:03]
[答：单词翻译]	simultaneous：同时取样
[问：jjkkww]	请您解答一下，高速A/D在应用中应注意的一些问题，以及其在EMC方面应该怎么做
[答： Wayne_Zhou]	Simply you need to note PCB layout, supply de-coupling, grounding, clk, digital signal buffer, impedance match. Normally you can find these kind of imformation from the datasheet, also you can refer to the material of below link:	[2002-11-26 11:05:05]
[答：单词翻译]	PCB layout：PCB布线 supply de-coupling：电源去偶 clk：时钟
[问：lb138@ etang.com]	如果ADC的参考电压为0~3.3v,而我需要双极性的输入电压，我该如何处理呢？谢谢！
[答： Eagle_Zhang]	Some ADC such as AD7665 have bipolar input in single supply. You can use amplifier such as OP1177 to add an middle level DC. You can use single end to different amplifier such as AD8138 to input an different input ADC.	[2002-11-26 11:05:13]
[答：单词翻译]	bipolar input：双极输入 different amplifier :差分放大器
[问： david2002guo]	数字示波器的ADC一般都选用什么样的ADC(采样频率和位数),如果有的数字示波器是60M带宽，1GS采样率，ADC也是1GS吗，ADI有这么高的采样速率的ADC吗?如果有，用什么接口把数据传出来呢？
[答： Wayne_Zhou]	At first, we're sure it's not 1Gs sample rate. So the detailed request you should refer to professional provider (ocsilloscope manufacturers).	[2002-11-26 11:06:05]
[问：ustcwwb]	ADC前端的信号调理有几种 各有什么特点？
[答：Liao_ Wen_Shuai]	There are a lot of signal conditionings in the ADC front-end. Amplifying, filtering and so on. Also, the selection of the conditioning scheme depends on the sensor you used. Please refer to the below link for more information: http://www.analog.com/technology/amplifiersLinear/ training/sensorSignal.html	[2002-11-26 11:06:36]
[答：单词翻译]	front-end：前端  Amplifying：放大  filtering：滤波
[问：hqhtn]	现在的高速ADC在设计上，怎样考虑电源、地平面的铺设减少噪声确保转换精度和可靠性？能否提供一些具体的测试实例或分析仿真结果，不要只是定性的描述。谢谢。
[答：Liao_ Wen_Shuai]	OK, in fact we have the materials that explain in detail to this question with examples. Please refer to the link below: http://www.analog.com/technology/amplifiersLinear/ training/highspeed.html	[2002-11-26 11:08:27]
[问： zhaobingchina @hotmail.com]	如果我需要设计产生和测量失真度小于0.01%的正弦波(1~200Hz,0.1~10V)，请问需要采用何种ADC和DAC，谢谢！
[答： Wayne_Zhou]	You need to choose ADC/DAC with at least 14bits resolution, sample rate higher than 400hz, and input in your range. You have so many choice in ADI product. So you need to get more spec of the system request, to get better choice. You can send email to china.support@analog.com for further question.	[2002-11-26 11:09:05]
[问：wylinder]	请问AD转换器的输入端的滤波电容同AD转换器的采样速度有何关系？假如我需要的采样速度是20K，那么模拟输入端的电阻和电容如何选择比较合适？
[答： Wayne_Zhou]	The RC time constant will restrict your ADC through rate, but it also depends on ADC resolution. So you need to calculate the time which is enough for the ADC input to acquire the signal with accuracy range.	[2002-11-26 11:09:45]
[答：单词翻译]	RC time constant ：电阻电容时间常数
[问：wandfu]	因为我以前基本没有弄过硬件方面的,所以对硬件比较外行,但最近因为需要自己采集信号所以有个问题想问一下: 从电荷耦合器件从来的信号经过A/D时,需要考虑哪些因素?谢谢!!
[答： Charles_Lee]	You should thinking the video buffer before you connect to the ADC. Usually, the CCD output need to drive a long cable that CCD is not allow to drive such high capacitance load. A good low noise OP-Amplifier is your first choice. The ADC you can used from ADI are, AD9826 (linear CCD), AD984x(area CCD).	[2002-11-26 11:10:02]
[问：zhuqiqi]	请问用于视屏图像的采集的ADC与其它的ADC的区别？目前贵公司有哪些ADC芯片用于视屏图像的采集？
[答： Wayne_Zhou]	Video ADC is designed to meet video signal bandwidth, sample rate, and different video format. ADI have video decoder ADV7185, ADV7183 at present. Also we've AD9884/9883 for LCD monitor.	[2002-11-26 11:10:05]
[答：单词翻译]	video format：视频格式 video decoder：视频解码器  LCD monitor：LCD监视器.
[问：leasun]	串行模数转换器与并行模数转换器相比，各自有什么优缺点？
[答： Eagle_Zhang]	Serial port has less pin, small PCB space, low cost, low power consumption. Such as AD7680, 16bit 100K SAR ADC with only 6 pin SOT23 package. But normal only for low speed ADC. Parral port has wide band width, can support very high sampling rate, AD6645 can sopport 14bit 105MHz, AD9238 can support dual ADC with 65MHz with 24bit width parallel port.	[2002-11-26 11:10:50]
[答：单词翻译]	Serial port：串行端口 Parral port：并行端口
[问：jdchenjian]	自已用运放设计双积分式ＡＤＣ，应选用多大的积分电容，积分电流，和积分时间比较合理．
[答： Charles_Lee]	Designing ADC with discret components is not good on the point of cost, performance. Modern circuit design of ADC chip is very moture, so you've so many option in ADI ADC product.	[2002-11-26 11:11:05]
[答：单词翻译]	discret components：分立器件
[问：salon.liu]	如何在软件中设置ADC的基准.
[答： Wayne_Zhou]	For Sigma Delta and Pipeline ADC, it's difficult to set reference outside. But for other architecture ADC, you can use a DAC for out reference, then you can set the reference by digital input from MCU or DSP.	[2002-11-26 11:12:05]
[答：单词翻译]	reference outside：外部基准. digital input：数字输入
[问：microtech]	1.基于Sigmal-Delta调制的ADC和pipeline的ADC的发展前景如何，什么是这两种ADC设计中的最大的挑战。 2.关于DAC的问题，基于sigmal-Delta的DAC和基于PWM调制的DAC有很多的相似之处，两种类型各自的优缺点是什么，发展的前景如何。
[答： Charles_Lee]	Prospective for both, they're main-stream ADC product. Sigma-Delta mainly are used in industrial field, and pipeline in high speed design. Their advantage and shortage please refer to page 41 and 47 on the seminar. Sigma Delta DAC has better resolution performance, (We'll have another seminar in December, welcome to attend)	[2002-11-26 11:13:05]
[答：单词翻译]	main-stream ：主流
[问：zhlsun]	1. A/D前,应采用何种低通滤波器(有源还是无源). 2. 模拟输入电压大小受那些限制
[答： Wayne_Zhou]	1) It depends on you application, and system request. Basically you should note that active filter can bring gain, but noise as well, passive filter is without gain, so has some power loss, but with better noise preformance. You can refer to below link for active filter design as guide: http://www.analog.com/techSupport/designTools/ interactiveTools/filter/filter.html. 2) Analog input amplitude should be refer to the request of the concerned ADC datasheet.	[2002-11-26 11:14:05]
[答：单词翻译]	active filter：有源滤波器 passive filter：无源滤波器 gain：增益, power loss：功率损耗, noise：噪声 datasheet：数据手册.
[问：qin]	ADC在什么情况下容易丢码？如何防范？介绍中的几种ADC结构，那种较为容易丢码？
[答： Mike_Byrne]	Assuming that an A/D converter is specified with no missing codes, then the no missing codes performance will depend on how the part is applied. Factors such as decoupling, grounding, shielded inputs, analog input buffer, stable reference etc will affect the no missing codes performance. Assuming good design of the A/D converter, all A/D converter architectures can provide ADCs with no missing codes. However, sigma delta ADC architectures are generally the best architecture to provide the highest possible no missing codes performance. However, most ADI A/D converters do provide no missing codes performance - each datasheet should be checked to see if this is guaranteed for a specific part.	[2002-11-26 11:14:22]
[答：单词翻译]	missing codes：丢码 shielded inputs：屏蔽输入,
[问：ljp]	DNL和INL，对失真的影响，那一个较大？
[答：Liao_ Wen_Shuai]	Normally, if the DNL is larger than 1 LSB, then code will be missed. The INL measures the linearity of the ADC. All of them will cause distortion to the output. But ADI has used some technologies to compensate for this, dither and shuffling technology mentioned in the seminar are these kinds of technology.	[2002-11-26 11:14:22]
[答：单词翻译]	distortion ：失真
[问：qin]	目前ADI的ADC取样频率能达到多少？除了和带宽有关外，它对ADC的性能有什么影响？
[答： Charles_Lee]	We will have the 500MSPS will come out later on. But the released parts is up to 250MSPS (AD9480-8bits), 210MSPS(AD9410-10 bits).	[2002-11-26 11:14:55]
[问：funzhx @sina.com]	我见过的A/D是ADS7806，这个片子是不是有一个外围的校正电路？校正电路是怎样的呢？还有ADS7806的27和28脚是两个参考电压的输入，有些情况下是不是可以连在一起使用，这样会不会影响AD的准确性呢？
[答：Charles_Lee]	This is not ADI product. You can choose AD7892/93/94/95.	[2002-11-26 11:15:05]
[问：zzkapok @163.com]	是不是采样率越高越好？
[答： Wayne_Zhou]	Yes, normally it can improve the SNR performance, but you should consider your system design request.	[2002-11-26 11:16:05]
[答：单词翻译]	SNR：信噪比
[问：ljp]	高精度ADC，对取样保持电路有何特殊要求？
[答： Wayne_Zhou]	Settling time for mux is very important. others please refer to a useful guidance on below link: http://www.analog.com/technology/ amplifiersLinear/training/practicalDesign.html	[2002-11-26 11:16:12]
[答：单词翻译]	Settling time：建立时间
[问：wylinder]	thank you sir! but how can I choose adc if my maxium sample speed is 8k, how much is the adc conversion speed?
[答： Eagle_Zhang]	Normall sample speed is the same as sample rate, such as SAR type ADC. If you use Sigma-Delta ADC such as AD7730, you should use a very hign sample clock. Please refered to Datasheet.	[2002-11-26 11:16:25]
[问：henan ying2002]	ADC的转换精度和转换速度与哪些因素有关？在选择时应该注意哪些问题？
[答： Charles_Lee]	ADC' resolution and through rate depends on their architecture and processing. You can refer to ADC datasheet for relative spec.	[2002-11-26 11:17:05]
[答：单词翻译]	resolution：分辨率  through rate：转换速度 architecture ：结构 processing：处理过程
[问： nihaohong]	AD转换的操作在使用SPI接口时，主机方式与从机方式如何选择？是否有一定的规律。
[答： Charles_Lee]	If you're mentioning about the relationship between MCU/DSP and ADC, basically you should choose digital processing unit (MCU or DSP) as Master. But if you're design some industrial data acquisition system, or instrument, please note we've ADuC8xx which integrate ADC/DAC and MCU, flash memory in a single chip, which can be more easy for your design.	[2002-11-26 11:18:05]
[答：单词翻译]	data acquisition system：数据采集系统 instrument：仪器
[问：phyhust]	对于多通道串行ADC,如果每个通道要采集的信号频率不同，怎样设定各个通道的信号采集率？
[答： Eagle_Zhang]	Normal use the maxim sample rate for all the channel. AD7490 (16 channel 12bit) has a sequency in side, will automatically change from one channel to another. If different, it"s much difficult to control.	[2002-11-26 11:18:26]
[答：单词翻译]	channel：通道.
[问：TI]	调制器输出的1位量化信号流只有1位，表达精度很低，其信噪比，即信号x（n）的FFT X（k）的平方和与通带内其他谱线的平方和的比（对吗？）还能达到理论公式计算的值吗？
[答： Wayne_Zhou]	Yes, please refer the seminar for the principle of Sigma Delta ADC, on the page of 44 and 45.	[2002-11-26 11:19:06]
[问：wangf]	单电源ADC的电源地接模拟地好，还是接数字地好。如果接模拟地如何防止数字地的串扰。
[答： Charles_Lee]	You should connect to analog ground. To separate the interference from digital ground, you need to use one-point ground technology. You can refer to materials of below link:http://www.analog.com/technology/ amplifiersLinear/training/highspeed.html, or http://www.analog.com/technology/amplifiersLinear/ training/sensorSignal.html	[2002-11-26 11:19:10]
[答：单词翻译]	analog ground：模拟地
[问：TI]	3。对sigma-delta ADC，由于对降低通带内噪声的作用不同，选择过抽样比和调制器阶次之间的制约和优先关系是怎样的？高阶调制器的不稳定性又是如何消除的？
[答： Wayne_Zhou]	Please refer to application note# AN-283, AN-388, AN-389, which you can download from www.analog.com	[2002-11-26 11:19:15]
[问：wylinder]	对于温度等模拟量的采样经常使用桥式电路，使用该电路有何好处？对于该桥式电路的电压放大需要注意那些？使用什么样的放大器更合适？
[答： Charles_Lee]	it's used for small signal accurate measurement. It's easy to cover problem of temparature shift, linearization. This technology is widely used, for example, you can use AD7730 directly for bridge circuit. You can refer to the materials of below link: http://www.analog.com/technology/amplifiersLinear /training/sensorSignal.html	[2002-11-26 11:19:55]
[答：单词翻译]	small signal accurate measurement：小信号精度测量 temparature shift：温度漂移 linearization：线性化 bridge circuit：桥式电路.
[问：TI]	3。1、信号带宽较窄时，考虑到量化噪声整形，又为了尽量减少调制器的阶次，过抽样比最大能加大到多少？在不同的工艺下是不是关系不同？
[答： Charles_Lee]	Please refer to application note# AN-283, AN-388, AN-389, which you can download from www.analog.com	[2002-11-26 11:20:05]
[问：stone _chenlei]	对于干扰比较严重的检测环境,除了选择双积分型A/D芯片外,其他几种类型的A/D芯片,选用那一种比较好?
[答： Charles_Lee]	I would like to suggest you to use the ADC with differential input ADC to avoid the noise interference.	[2002-11-26 11:20:12]
[问： carnivorous]	1.二阶过采样为128倍，一位量化的Sigma—Delta AD的理论上可以达到16bit的精度，在实际低频情况下可以达到多少位？原因是什么？ 2。如何验证sigma—delta AD调治器的信噪比？ 3。请讲一下Pipeline AD 中数字纠错的原理。谢谢！
[答：Liao_ Wen_Shuai]	1. It can reach 24-bit in parctice. The reason is the noise shaping technology used in this kind of ADC. For more information you can refer to the following three application notes provided by ADI: AN-283, AN-388, AN-389	[2002-11-26 11:20:40]
[答：单词翻译]	noise shaping technology：噪声改善技术
[问：ADCshuiling]	How to eliminate the gain errors?
[答：Cindy_Bl oomingdale]	You can adjust the reference of an ADC to adjust for gain errors.  The full scale range of the ADC tracks reference voltage changes.  In many ADCs, to adjust the reference, you will need to use an external reference. If you would like to match the gain of two ADCs, you can set one ADC as the "master" ADC.  Then, adjust the reference of the second ADC to match the first ADC.	[2002-11-26 11:20:57]
[答：单词翻译]	full scale range:满刻度范围   external reference：外部基准电源.
[问：qin]	INL是如何产生的？它和那些因素有关？
[答： Mike_Byrne]	The design factors which affect INL varies somewhat depending on the A/D architecture. For SAR architectures, the factors which affect performance are the linearity of the DAC used in the SAR architecure, the linearity and noise performance of the comparator and the linearity of the Sample-and-Hold amplifier. For pipelined and Flash ADCs, similar factors affect INL performance as those just outlined although the pipelined and error correction techniques attempt to make the part more immune to DAC and comparator errors. In sigma delta architectures, the primary source of INL error is the voltage coefficient of the sampling capacitor.	[2002-11-26 11:21:27]
[答：单词翻译]	Sample-and-Hold amplifier：取样和保持放大器  error correction ：误差修正 comparator ：比较器 .
[问：yjm888]	1.多通道高速模数转换器的设计应用要注意的问题。 2。采集两路300-4000KHz音频信号选用什么型号的A/D芯片最合适？
[答： Wayne_Zhou]	1. Simply you need to note PCB layout, supply de-coupling, grounding, clk, digital signal buffer, impedance match. Normally you can find these kind of imformation from the datasheet, also you can refer to the material of below  link:  Http://www.analog.com/technology/ amplifiersLinear/training/highspeed.html 2. You can use AD1870/1871/1877.	[2002-11-26 11:21:28]
[问：du8800]	请问专家： 9对ADC）PCB设计时，有关地的处理，有人说数字与模拟分开最终会集电源的大电容处，有人说此两地线应再ADC下方相接，4层板有人赞成此两地分离隔开，也有人赞成不分开隔离，只在布局时分块，而地平面用统一的地平面 我应怎样来处理？对2层和4层请分别指教，谢谢！
[答： Eagle_Zhang]	The is some different in high speed and low speed. For high speed (>10M SPS), use a signal Ground in layer 2 of 4 layer, bottom layer in 2 layer PCB. For low speed ADC (< 1M SPS) use signal connect point under ADC or at power connect point (need two diode near ADC to protect). For the meddle speen (1M ~ 10M), depends on detail application.	[2002-11-26 11:22:44]
[问：ljp]	ADI公司有没有特殊变换率如电话中的A律的模数转换器？
[答： Charles_Lee]	Sorry, we don"t have this kind products.	[2002-11-26 11:24:20]
[问：lq_3791 @sina.com]	怎么将100个以上的模拟信号（v、i）转换成数字信号与微 机接口实现自动控制。谢谢！
[答： Wayne_Zhou]	From input point, you can use MUX. From output point, you need to control digital signal communication among different ADCs, maybe RS232 or 485 is need to transmit the data to central PC.	[2002-11-26 11:24:54]
[问：flyboy]	请问可用于8位单片机（8051系列)声音与视频数据采集的ADC有哪些？各有什么特性？谢谢！
[答： Wayne_Zhou]	Please check ADuC812, with ADC/DAC/MCU/Flash on the same chip.	[2002-11-26 11:29:04]
[问：jgjsty_cn]	请问：模数转换器的分辨率和动态范围的关系？为什么有些芯片的动态范围和转换精度不对应？谢谢！
[答： Charles_Lee]	1. The Dynamic Range (or SNR) = 1.76 + 6*N(bits). 2. This might caused by the ADC core design	[2002-11-26 11:29:25]
[问：richard@a yuttha.com.tw]	What kind of jitter in SHA will introduce noise or distortion to ADC? Cycle jitter? or cycle to cycle jitter?
[答： Nicola_OByrne]	Usually its Cycle to Cycle Jitter that will introduce noise or distortion into ADCs. Its the jitter that varies the sampling interval that introduces the jitter into the ADC result. For SAR ADCs this is jitter from CONVST edge to CONVST edge and for Pipelined ADCs from clock cycle to clock cycle. Equidist Sampling is the key to avoiding this.	[2002-11-26 11:31:02]
[问：hzkq]	Please introduce the perfermence of the ADC&DAC in ADuC824, and what we will pay more attention for?
[答： Eagle_Zhang]	ADuC824 has one 24bit ADC and 16bit ADC, two 12bit DAC, 8K flash and 8052MCU. 24bit no missing code, 18 bit at Range = ±2.56 V @ 20 Hz Update Rate Bits p-p typ. Please refered to datasheet. Please add ADM810 reset chip for ADuC812 (8 ch 12bit ADC, 8K menory), ADuC816 (16 bit ADC), ADuC824 (24bit ADC). But no ADM810 need for ADuC814(28 pin TSSOP), ADuC831 (8 ch 12 bit ADC, 62k flash), ADuC832, ADuC834 (24bit, 62k flash), ADuC841 (fast MCU).	[2002-11-26 11:31:31]
[问：xlwise]	在开关电源的设计过程中，运用I2C接受外部控制信号来调整开关电源的输出电压。在这种情况下如何正确选择合适的ADC？并且应关注哪些重要的参数？
[答： Charles_Lee]	This application should use DAC here. The INL/DNL and output stage (current or voltage) are you considerations.	[2002-11-26 11:31:44]
[问：Jlee]	How about the drifting? What are special need pay attention to to get best performance? Though they are challanging for ADI.
[答： Mike_Byrne]	Most ADI converters are specified over temperature so the effects of drift are already included in the specification. The datasheet for a particular product of interest should be read to ensure that the specifications do apply over temerature. Some parts give the full specification over temerature while others also include drift specifications. Reference drift error is a common source of temperature drift error. If this is an important parameter, it is generally better to provide a reference with a low ppm TC (although some newer converters do provide on board references with good TC performance). Apart from that, good applications practices such as low impedance grounding and signal traces are important. Also, for some applications the use of chopper-stabilised ampliifers in the signal path may be necessary to reduce offset drift in the analog input path.	[2002-11-26 11:37:12]
[答：单词翻译]	Reference drift error：基准漂移误差  TC ：温度系数 chopper-stabilised ampliifers：斩波稳定放大器   offset drift：失调漂移
[问：lunali]	您好！ 目前，我想选用AD公司的AD574A对我要处理的信号进行采集。AD574的一次转换时间为25us，而我的信号脉冲的周期为8us请问比AD574转换速率更高的芯片型号，哪里可以下载到相关资料？ Thanks you for your answering my question!
[答：Liao_ Wen_Shuai]	OK, I think you can choose a ADC with the throuput larger than 125KSPS, and the input voltage is +/- 10V. AD7862/63/64, AD7891/92/95 can be used. For pin compitition, AD774 can be selected. You can get these information from the www.analog.com, or send mail to china.support@analog.com to request for CD-R and other technical support.	[2002-11-26 11:38:08]
[问：cruos]	问：ADI公司的高速ADC中12位的最快的可以达到210MSPS，请问怎样设计这样的数据接口和存储，以及评估处理的速度，如果做频谱分析用FPGA好，还是DSP好，若用DSP并行怎样确定共享的连接？ 另假设要采集更高的信号（例如150MHz的带宽），是否可以用并行工作的方法实现而只用内部的采样保持电路（用分相时钟？）？
[答： Charles_Lee]	AD9430 can up to 210MSPS. On this architecture, we provide dul channels output. Your design have to provide this dual data interface for it. For the spectrum analyzer that I would like to suggest you to use DSP such as ADSP-21161 on this that he not just only provide the FFT calculation but also the memory and output management. For higher BW design, you can use dual ADCs in parallel to achieve it but you have to consider the two ADCs miss-match and the buffer drive capability issue.	[2002-11-26 11:40:30]
[答：单词翻译]	MSPS：每秒百万次取样 dual channels output：双通道输出spectrum analyzer：频谱分析仪  FFT ：快速傅立叶变换
[问：TI]	7.对于咱公司的大部分sigma_delta ADC,梳妆滤波器、半带滤波器及FIR低通滤波器在各级一般是如何先后安排的？半带滤波器在抽取时会有少量的混叠，影响大吗？使用中只是不用作最后一级就可以了？ FIR滤波器的纹波系数一般是百分之几？
[答： Eagle_Zhang]	AD7730/AD7730L SIGMA-DELTA MODULATOR The first stage filter is a low-pass, sinc3 or (sinx/x)3 filter whose primary function is to remove the quantization noise introduced at the modulator. The second can run Normal FIR Operation. SINC3 will have bigger alias. But the data rate is much high in first stage, it will not cause issue for small band width signal which is intersted. Please refered to AD6620 (digital receiver with CIC2, CIC5, and 256 tap FIR) data sheet.	[2002-11-26 11:42:09]
[答：单词翻译]	quantization noise： 量化噪声 modulator：调制器
[问：samire]	有没有带I2C接口的ADC？
[答： Nicola_OByrne]	Presently for our I2C offering we have the AD7417/AD7418 10 bit, 4 channel ADCs with on chip temperature sensor. However we are also working on a new family of I2C ADCs, the AD7992. This is a 12 bit 2 channel ADC with I2C interface. This new family of I2C ADCs will offer the Hs-Mode I2C interface in addition to the Standard and Fast I2C mode. Also in this I2C family we hope to offer 4 and 8 channel 12-bit and 10-bit versions.	[2002-11-26 11:42:55]
[问：qin]	取样频率如何正确选取？它和那些因素有关？
[答： Charles_Lee]	This is dependent on the input signal BandWidth. Theoretically, the sampling rate have to bigger than signal BW than 2 times. But in the real world, we choose >4 times.	[2002-11-26 11:43:04]
[问：LIUCL]	在ADC的应用中，信号、ADC、CPU、电源等部分的模拟地和数字地应如何连接？
[答： Eagle_Zhang]	Signal point at low frequency, whole ground layer and connect as near as possible for hign spee. Please refer befor answer.	[2002-11-26 11:44:28]
[问：samire]	ADC的电源去耦电容一般多大合适？从那几方面考虑？
[答： Charles_Lee]	0.1 uF normal case. You have to use the low ESL capacitor there if the simpling rate is high.	[2002-11-26 11:45:02]
[答：单词翻译]	ESL ：等效串联电感
[问：phyhust]	对于SAR型ADC,每进行一位转换需要一个时钟周期，请问该时钟周期一般是ADC内部提供还是由外部提供？
[答： Charles_Lee]	Internal.	[2002-11-26 11:45:26]
[问：tjl]	请介绍一下嵌入式ADC与通用ADC的主要区别
[答：Liao_ Wen_Shuai]	There is no function and performance difference between them. Only the access type to them is different. You can find the information of the embedded ADC from ADuC812/814/816/832 and so on.	[2002-11-26 11:45:28]
[问：Anoymous]	3.3V工作电压的16位AD converter，理论上应能够分辨出3.3*1000000/65535=50.35μV的电压变化，但通常数字模拟混合电路板的噪声电压要远远大于这一数值,例如电压基准源LM336-2.5的标称电压变化典型值为2.6mV，请问高精度的ADC在电路板布线和选择ADC的模拟参考电源方面的要求是什么？提高ADC采样精度的措施有哪些？谢谢。
[答： Wayne_Zhou]	Therefore the reference accuracy is very important, so you just need to select best reference. For precision ADC, you need to note PCB layout, supply de-coupling, grounding. Also you can use oversampling, nose shaping (sigma delta) ADC, and other technology. All you do is to maximumly decrease various noise. You can also refer to the material of below link: http://www.analog.com/technology/amplifiersLinear /training/sensorSignal.html	[2002-11-26 11:45:34]
[答：单词翻译]	oversampling：过取样
[问：ecnanji ng_EBY7E]	在DC/Dc 的频率与ADC采样频率相当是对噪声，精度的影响很大。如何克服，有没有简捷的方法？
[答： Charles_Lee]	In such case, I would suggest you to add the C-L-C filters on the power supply side and after that, use a LDO to remove the noise. The ADC layout should keep far away with the DC-DC converter.	[2002-11-26 11:47:28]
[答：单词翻译]	LDO ：低压降
[问：wguan glinseu]	请问ADC的增益、失调微分非线性和积分非线性是怎么测试的，有ADC的系统仿真模型吗？如果有，ADC的仿真模型是用什么语言描述的，能提仿真模型吗？
[答： Charles_Lee]	ADC has our own internal model used on this. We use the sawtooth wave to test the INL/DNL specifications on our ATE machine.	[2002-11-26 11:49:16]
[答：单词翻译]	sawtooth wave： 锯齿波
[问： geyunfeng]	模拟电源和数字电源一定要分开吗？如果用一个电源会带来什么影响，怎么克服用一个电源带来的影响？
[答：Liao_ Wen_Shuai]	Normally, it is better for you to separate them. But, you can use the same voltage source for Analog and digital VDD of the ADC. You can find the use of them from the datasheet of the ADC you selected. If you have to use the same voltage source for the analog and digital VDD, then use filters between them. You can find more information from the links below: http://www.analog.com/technology/amplifiersLinear /training/highspeed.html http://www.analog.com/technology/amplifiersLinear /training/sensorSignal.html http://www.analog.com/technology/amplifiersLinear /training/practicalDesign.html	[2002-11-26 11:49:31]
[问：zhxf00]	请问在超声诊断系统设计当中，采用dual-ADC(40M)需要注意哪些问题？
[答： Eagle_Zhang]	If you use AD9283(8 bit 100M) or AD9238 (65M 12bit), please pay attentation to PCB lay out and power decouple. Because there are many ADC in Ultrasonic equipment, you can use AD8231 or tranformer to convert signal end to differential. Please also pay attention to clock. A low noise jetter is need. A good crystal clock is perfered. (You can also use ADF4213 PLL to generate far clock than 1GHz then devide down to 40MHz.)	[2002-11-26 11:49:50]
[答：单词翻译]	Ultrasonic equipment：超声波设备 tranformer：变压器  low noise jetter：低噪声抖动  crystal clock ：晶振 PLL：锁相环
[问：chen_pin]	我在有的ADC的DataSheet种看到温度误差时1～2LSB,是不是14位精度的AD芯片实际最高只有12～13位的精度？温度影响真的哪么严重么？谢谢！
[答： Wayne_Zhou]	It"s different from different ADC to ADC. You can choose those with better temparature performance, or you can choose outside Ref which can bring better accuracy.	[2002-11-26 11:50:48]
[问：hudazym]	如果在传感器中采集到的是非常弱且及其快消逝的信号AD or DA 有何要求？
[答：Liao_ Wen_Shuai]	You can select the high speed T/H in your circuit, or selcet the ADC with embedded high speed T/H. Then you can trigger the T/H or ADC when signal comes in.	[2002-11-26 11:53:48]
[问：aisy78]	AD6640对时钟输入有什么要求？为什么要通过变压器输入？
[答： Eagle_Zhang]	Low clock jetter is need for hagh speed ADC such as AD6640 (12bit, 65M ) and AD6644 (14bit, 65M). The signal-to-noise ratio (SNR) for an ADC can be predicted. When normalized to ADC codes, Equation 1 accurately predicts the SNR based on three terms. These are jitter, average DNL error, and thermal noise. Each of these terms contributes to the noise within the converter. A 1ps clock jetter is pefered. Please refered to AD6644 datasheet or our High speed design techniques.	[2002-11-26 11:56:34]
[问：ffffff57]	如果在线路中很难保证接地良好，应该怎么减小接地噪声的影响？
[答： Charles_Lee]	Use differential signal path.	[2002-11-26 11:58:09]
[问：大胡]	我现在正在做一个采集纳伏数量级的数据采集卡,是基于计算机ISA总线的.采集这样的微弱信号,要用到低噪声,高精度放大器,然后再接至AD,如何解决阻抗匹配的问题?设计电路的时候有哪些原则?
[答： Eagle_Zhang]	Use JFET such as AD8610 input OP if for high impendence source. The ADC should driver by a hign signal level AMP. Please pay attentation to lay out , shielding and power supply. Use a DC-DC then use Lineary regulate such as ADP3335 LDO.	[2002-11-26 11:59:59]
[问：qin]	什么是全功率带宽（PFBW）？对ADC有何影响？
[答：Cindy_Bl oomingdale]	Defined as the analog input frequency at which the spectral power of the fundamental frequency is reduced by 3 dB.  The full power bandwidth is often limited by the slew rate of the internal circuitry.  Many of our high speed converters are used in IF sampling applications (where the input frequency is higher than the Nyquist value).  Therefore these converters have large FPBW.	[2002-11-26 12:02:14]
[答：单词翻译]	spectral power of the fundamental frequency ：基频的频谱功率
[问：大胡]	我用过贵公司的AD9850,但贵公司提供该芯片的资料提供了两种时序图,不知道如何解释?
[答：Eagle_Zhang]	There are different timing sequence for different modle. Please pay attention to inside update and external. External update is suggest after change frequency.	[2002-11-26 12:02:36]
[问： carnivorous]	在PIPELINED ADC中,采样速率是30M,那么运放在30M时的放大倍数应该达到多少呢?
[答： Charles_Lee]	I think this should be the bnadwidth issue than the gain. The OP-Amp -3db BW should better than 15MHz.	[2002-11-26 12:03:05]
[问：hansh ang_007]	专家！8路的ADC在使用时，相互之间会有影响吗？要是有，怎么才能避免？谢谢
[答：Wayne_Zhou]	It depends on the ADC you choosed. Crosstalk is important spec you should note when you select ADC. From the point of extra circuit design, you need good PCB layout, sheltering, and de-coupling.	[2002-11-26 12:03:43]
[答：单词翻译]	Crosstalk：串扰
[问：mbch8520]	24位ADC中,有没有自带比较电压的芯片,它的最大转换速率是多少?
[答：Liao_ Wen_Shuai]	Yes, we have this kind of ADC. AD7710 1KSPS AD7711/7711A    1KSPS AD7712   1KSPS And so on. You can find them from the www.analog.com	[2002-11-26 12:04:12]
[问：samire]	ADC中比较器的失调是自动调零的吗？校准时间要多长？
[答：Nicola_OByrne]	Generally the Offset of the comparartor in the ADC is the biggest contributor to the Offset specification outlined in all our ADC Datasheets. Thus the offset spec outlined on the specification page of datasheet will give a good indication of the offset of the comparator in the ADC. This a completely linear effect and will not affect linearity. In some of our ADCs we offer a digital calibration routine to eliminate the Offset in these ADCs.	[2002-11-26 12:08:18]
[问：大胡]	对于采集几十纳伏,频带为200~10k Hz的微弱信号,应选用什么ADC芯片?
[答： Charles_Lee]	You almost can not do it. Since the signal level is too small that no OP-amps can handle such small signal to amplify it to fit the ADC input range.	[2002-11-26 12:08:21]
[问：wylinder]	对于语音等的电路，经常在adc前段采用agc电路，该电路将如何设计？
[答：Eagle_Zhang]	Please us SSM2165 or SSM2166 Miceophone Preamplifiers and refered to the datasheet.	[2002-11-26 12:08:47]
[答：单词翻译]	Preamplifiers：前置放大器
[问：bby]	16位ad前向通道设计时抗干扰问题和精度如何保证?
[答：Wayne_Zhou]	At first, you need select high accuracy sensor, pricision amplifier (low offset, low bias, good temparature coefficient, etc.). About the interference problem, you need pay more attention on PCB layout, including de-couping, sheltering, grounding, etc. Details you can refer to below useful design guide: http://www.analog.com/technology/amplifiersLinear/ training/sensorSignal.html	[2002-11-26 12:08:50]
[问：hefeng]	我注意到在并行ADC中存在REF电压的选择问题。这个REF电压应该是由用户提供的吧，如果用户自己提供的电压不准或者不稳定，势必会造成转换误差。贵公司的产品是否会集成参考电压转换电路，用于为用户提供一个标准参考电压或者是一个稳定的电压？如果目前还没有，以后会予以考虑么？如果不予考虑，那么你们认为这么做的原因是什么，清从技术以及工艺的角度回答，谢谢！
[答：Liao_ Wen_Shuai]	In fact, we have a lot of ADCs embedded with voltage reference. Also, we have some very good voltage reference parts. You can find them from the link below: http://www.analog.com/technology/dataConverters/ designTools/selectionGuides/precisionvolt.html	[2002-11-26 12:08:59]
[问：cryscom]	请问专家，集成在数字温度传感器中的ADC是什么类型，使用时要注意什么？与分立进行温度采集有什么区别？哪个更好？
[答： Mike_Byrne]	Analog Devices provide temperature sensors on a range of different ADC architectures. We also provide a complete range of temperature-to-digital converters for temerature measurement applications. We can provide the on-chip temperature sensors on different ADC architectures. For example, we have a family of SAR ADCs with on-chip temperature sensors, the AD7416/AD7417/AD7418 and AD7816/AD7817/AD7818. We also have a family of sigma delta converters such as the AD7719 and provide temperature sensors on our microconverter products also. Most of our A/D converters provide on-chip temperature sensors while our temperature-to-digital converters allow for remote temperature sensors. Internal temperaure sensors sense the temperatuire where the A/D converter is situated. In some applications, it will not be practical to locate the A/D converter at the measurement point and therefore a remote temperature sensor will be necessary. Also, remote sensors allow for greater flexibility in the temperature sensing device used.	[2002-11-26 12:11:59]
[答：单词翻译]	microconverter：微转换器  temperature sensing device ：温度传感器件
[问：yws]	我门的d/a转换的增益和带宽矛等问题如何解决
[答： Charles_Lee]	Used current feedback amplifiers can solve this issue.	[2002-11-26 12:12:14]
[答：单词翻译]	current feedback amplifiers：电流反馈放大器
[问：chenjh_f269p]	能谈一谈电源对adc的影响吗thank
[答：Liao_ Wen_Shuai]	The voltage source will influence the performance of the ADC. If the voltage source is too bad, then the reference voltage will be imprecision, which will influence the performance of the ADC directly. You can find this information from the links below: http://www.analog.com/technology/amplifiersLinear /training/highspeed.html http://www.analog.com/technology/amplifiersLinear /training/sensorSignal.html http://www.analog.com/technology/amplifiersLinear /training/practicalDesign.html	[2002-11-26 12:12:33]
[问：ecnanji ng_EBY7E]	请问：在进行图象处理时采用了Pipeline ADC9 bit DSP 是不16位的对高8位和低8位数据拼接为保证末位不抖动，有什么高招。
[答：Eagle_Zhang]	If you use AD9883 for VGA input, the date rate is very high. If you use FIFO, there will be no issue. If you use buffer, please make sure every date is not missing. If you use ADV7183/ADV7402 to decode Video signal, the ouput is 8bit, there will be no issue. You can use ADSP21532 backfine DSP which has a 8 (total 16bit) bit parral port dedicated for video input.	[2002-11-26 12:13:51]
[问：linger_xy]	请问，单端输入和差分输入，各有什么优缺点？那些性能指标与输入的方式关系密切？
[答：Wayne_Zhou]	Single end input is simple. But differential input have good CMRR, and gound-noise protection, can offer better accuracy, anti-interference performance.	[2002-11-26 12:15:54]
[答：单词翻译]	CMRR：共模抑制比
[问：wangf]	I used an 16bit ADC,but it"s conversion time longer than sampling time 0f the system,if the 16-bit ADC used for a 12 or 14-bit ADC, whether the conversion time can be reduced?
[答： Mike_Byrne]	Normally, 12 and 14 bit converters can provide a faster conversion time than 16 bit converters. This is especially true of our high speed, pipelined ADCs. Right now, we have 16 bit SAR ADCs which provide a conversions rate of 1MSPS. We would need to know the specific requirements in your system to know if we could provide a 16-bit solution for your application.	[2002-11-26 12:15:59]
[问：chen_pin]	温度误差，在ADC采样过程中影响大么？是不是每个ADC都存在这样的问题？
[答：Liao_ Wen_Shuai]	The temp. shift will influence the performance of the ADC in some ways. But from the datasheet, you will find the influence to ADI parts is not very large. ADI will grantee the performance in the full range we specified.	[2002-11-26 12:16:36]
[问：大胡]	在采集微弱信号时,是否选择转换为数高的ADC一定比转换位数低的ADC好?
[答：Wayne_Zhou]	Basically it"s like this. But please note resolution doesn"t always means accuracy.	[2002-11-26 12:17:07]
[问：azmao]	A/D前是否必须要低通滤波,我利用AD7865进行多通道的信号采集,我关心信号的相位问题,滤波造成相位漂移,如何处理?
[答：Mike_Byrne]	It depends on the application whether a filter is required in front of the AD7865. The AD7865 itself does not require a filter but depending on sources of noise in the signal source, it may be necessary to provide filtering to avoid anti-aliasing issues. Filters on the front end do provide potential issues with phase shift across the various input channels.	[2002-11-26 12:18:59]
[答：单词翻译]	anti-aliasing ：反混淆
[问：vjliu]	在SD ADC电路中（例如18BIT），CLOCK JITTER 应控制在多少？
[答：Mike_Byrne]	Because of the very high oversampling rate which sigma delta converters operate with, there are generally much more immune to clock jitter than SAR or pipelined converters. However, care does need to be taken to ensure than any noise sources introduced by clock jitter do not appear in the banmd of interest.
非在线问答
[问：]	要学习模数转换器（ADC）的基本原理应学哪些基础？
[答：]	You can begin from some materials about analog and digital signal processing, according to the concept given by this seminar. Meanwhile you can find some materials at ADI website: http://www.analog.com/technology
[问：]	有无更快速的模数转换芯片？
[答：]	Depending on your system request, you can have many choice, for example, AD9410 as 10bit 210 MSPS, AD9480 as 8 bit 250MSPS, AD9054 as 8bit 200MSPS. You can contact with ADI local sales office or distributors for CDROM or other informations. Or you can get other part# by following website: http://www.analog.com/technology/ dataConverters/adc/standard/adc_matrix.html
[问：]	How to check YUV signal is right or&nbsp;&nbsp;not?
[答：]	Not sure what' the condition you're asking about. So, please contact with ADI local office or our distributors for detailed help.
[问：]	he ground is need separate or not?
[答：]	The principle for system grounding is: make the analog signal transient current separated from digital signal current as much as possible. The recommendation is usually to split the PCB ground plane into an analog plane and a digital plane. It is then further recommended that the AGND and DGND pins of a converter be tied together and that the analog ground plane and digital ground planes be connected at that same point. You can refer to the design guide at below website: Http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html
[问：]	ADC在什么情况下容易丢码？如何防范？介绍中的几种ADC结构，那种较为容易丢码？
[答：]	For ADC itself, code missing is caused by DNL. So you need to check DNL spec on the datasheet when you choose ADC.
[问：]	请问在设计数据采集卡时用单片机内部的adc还是用独立的ADC,哪个更好谢谢！
[答：]	If integrated ADC can meet your system request, surely it's better than choose an external ADC. Because integrated ADC in MCU is time and cost effective solution, with better performance from the point of interferences and PCB layout problem.
[问：]	如何保障转换的精度?
[答：]	At first you need choose good ADC, and sensor, amplifier, clock, and other component on the signal chain. Then it's a system problem, you need to set proper parameters for amplifiers (gain, for example), ADC (sample rate), and so on. At last it's PCB layout problem, you need to follow strictly the principles to make sure interference is as little as possible.
[问：]	if the sampling rate is same with pipeline and SAR, which situation of application that pipeline is preferred and which case SAR is a most favorate?
[答：]	We've listed the important advantages and shortages for different ADC architectures on this seminar, you can refer to it. Please note except sampling rate, you need also to consider some other specs, such as power consumption, pipeline delay, chip size, and resolution, to determine what ADC you need.
[问：]	我想知道ADC（模数转换的最基本的问题）谢谢！
[答：]	Please refer to the seminar file.
[问：]	ADI公司哪种芯片可以实现4通道同时采样（4通道并行50Ksps采样,内部采保），精度可以达到16bits？
[答：]	AD73360 is a widely used part which meet your request closely, with 6 channel synchronously convertors, at 64KSPS. Or you can consider AD7865
[问：]	模拟地和数字地可以连在一起么，对信号质量有影响么？
[答：]	With unproper grounding digital signal may influence analog signal, and finally cause converstion accuracy. The principle for connecting analog ground with digital ground is: connect it at the point where the AGND and DGND pins of a mixed signal devices are tied together. You can refer to the design guide at below website: Http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html
[问：]	我是一个新手，提不出什么有价值的东西，但是希望可以向前辈学习学习，因为我 这里是拨号，速度慢，而且讨论时间又是在上班，所以很不方便，但是却对这些理论的东西很感兴趣，希望可以对自己在产品的认识上有更进一步的了解，所以希望 专家可否把讨论的东西发给我，我的邮件是chen_yu_ke@163.com，非常感谢。
[答：]	Please download the file from ChinaECnet directly
[问：]	抱歉因工作可能不能准时参加，但非常感兴趣，能否请主持人将这次会议的问答结果发送到我的邮箱：wojiubushini@sina.com，谢谢
[答：]	Please download the file from ChinaECnet directly
[问：]	高精度的ADC（18位以上），使用时注意的原则是什么？
[答：]	At first you should take care of the clock, which should be with good jitter performance. The other one is mainly PCB layout.
[问：]	能否推荐12位4通道并行输出的A/D？
[答：]	You can consider AD7862, AD7864, AD7874, depending on other specs.
[问：]	Does any chip could pin to pin compatible with WM9705 . Because there are many PDA project in our application .
[答：]	We've AC97 codec, like AD1981,AD1885. But not pin to pin with WM9705. And ADI has some other parts for PDA, like Micro amp SSM2167-1, touch screen digitizer AD7873, headphone amp AD8592, digital POT, LDO, DC-DC, charge pump ADM8839, and so on.
[问：]	A/D的转换的精度的 进步跟那些因素有关
[答：]	It's depending on design technique, manufacturing process and designer's experiences. ADI has best advantages, and that's why our ADC has the leading position of the world.
[问：]	请问串行、小封装的10位-12位带内部基准源的A/D有哪些型号？哪里可购？价格？
[答：]	ADI has complete ADC family, you can check them at http://www.analog.com/technology/dataConverters/ adc/standard/adc_matrix.html. Or you can contact with ADI sales offices, or local distributors. You can find the contact information at www.analog.com
[问：]	AD电路设计中，电源部分应该注意哪些问题？
[答：]	Choose power supply with good performance, and using decoupling capacitors on ADC power supply pin. Details you can refer to the materials as: http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html
[问：]	请问可用于声音与视频数据采集的ADC有哪些？能否用于8051系列单片机？
[答：]	We've audio ADC AD1870/1871/1877, codec AD74322, and video ADC AD9843, , AD984x (CCD AFE)AD988x (FPD), video decoder ADV7183 ADV7185
[问：]	可以简单介绍一下数模转换器的原理吗？
[答：]	Please attend our 2nd section of this seminar on Dec. 19. We'll introduce DAC fundamentals.
[问：]	怎么样才能让输出的值更精确一些呢？
[答：]	Use good clock, precision amplifier, careful PCB layout including grounding.
[问：]	在高速设计中，如何降低数字地线引入的噪声？
[答：]	Careful PCB layout, digital output buffer can be helpful. Details please refer to the materials of: http://www.analog.com/technology/ amplifiersLinear/training/highspeed.html
[问：]	812上的ad 输入端口的典型接发
[答：]	Add an amplifier as a driver for the ADC input. Please refer to ADuC812 datasheet: Driving the A/D converter.
[问：]	采集视频信号应该选那种ad?
[答：]	ADV7183(Analog Video to Digital YCrCb Video Decoder support NTSC-(M/N), PAL-(B/D/G/H/I/M/N). Similar part are ADV7185. There is also ADV7202(Simultaneous Sampling Video Rate Codec), ADV7402(HDTV&SDTV video Decoder support NTSC/PAL/SECAM/480p/625p/720p/1080i). And we have AD988x(110/140/170MSPS RGB Analog Interface for Flat Panel Displays) and all other video amplifer, switch and mux, etc.
[问：]	请问用AD测量基准源并不能输出满刻度值，为什么？
[答：]	ADC has an offset error, one is at 0 input, another is at full input.
[问：]	是否在A/D转换前均要进行有源低通滤波，如果我的采样频率是1440Hz，是否我的低通滤波的截至频率要在低于720Hz以下
[答：]	Yes. But you must use band pass filter if you use undersampling.
[问：]	能否再解释一下DNL和INL的概念
[答：]	To be simple, DNL it the error of each step with the ideal step. INL is the biggest error form the line.
[问：]	ADC的发展趋势如何？目前最急需改进的地方是什么？谢谢
[答：]	High speed, low power, small package.
[问：]	关于双极型模拟信号进行A/D转换时，需要对选择的芯片考虑哪些方面？ 另外，我现在要做一个数据采集系统，需要对－0.25v——0.75v的模拟信号进行8bit的A/D转换，采样率为1.25M，请帮我推荐一款A/D器件，谢谢。
[答：]	Normally you should choose a bipolar input ADC for the bipolar. But you can use an amplifier with an middle DC level in order to dirver an unipolar ADC.You can also use differenctial output type (such as AD8138) to driver an differential input ADC. AD8138 has an middle voltage input pin to give the overall DC offset.
[问：]	请问专家，在使用ADC的时候，怎样处理好数字地和模拟地的布线，怎么样布线才能使ADC更稳定？hanshang_007
[答：]	For the precision and audio ADC (less than 1MSPS), separate AGND and DGND and connect AGND and DGND in a single point. For high speed ADC (great than 10MSPS), use a single ground plane and contact all the AGND and DGND to this ground plane as short as possible. For 1MSPS to 10MSPS, it depends on system.
[问：]	专家!假如ADC的参考电压应该是5V，但是实际上是4.95V,那怎么才能校正呢?谢谢
[答：]	Correct in your software, it's much easy. But use ADI refernece such REF195, it will be very precision.
[问：]	各类AD转换器在PVT corner方面是怎么考虑及实施的？
[答：]	Sorry, I do not understand what you mean.
[问：]	设计中可能需要Sigma-Delta ADC 24位， 请问哪个公司提供可靠低功耗的硬核设计？
[答：]	ADI has many good design.
[问：]	那一种A/D抗干扰性能最佳，应用在工业现场那一种好？
[答：]	Normally bipolar type. New CMOS technical will be also OK if the circuit is a good design.
[问：]	三积分方式仍然有很多人在用，这种方式的有何新发展？有没有这种方式现成的IC或模块？
[答：]	The new developed Sigma-Delta can also reach more than 24 bit.
[问：]	when we convert high frequency signal,What questions should we pay attention to ?
[答：]	Clock jetter and grounding, power decouple, etc
[问：]	要采集微弱信号,首先考虑的是如何选择高精度,低噪声放大器和高精度ADC,那么如何解决放大器与高精度ADC的阻抗匹配问题呢?有哪些原则?
[答：]	The output of an amplifier is normally in low impendence, and the input of an ADC is normally in high impendence. There will be no problem to use an fast amplifier to driver ADC. Use 50 Ohm serial resistor for high speed types.
[问：]	一般AD芯片转换位数高了,采样率就会下降,如何解决这个问题?
[答：]	This is only for Sigma-Detla type (such as AD7738). If you use an SAR (AD7675) or piple line (AD6644) type, there will be no this issue.
[问：]	串行ad使用的过程中，有时发现数据为0的情况， 而并行ad则没有，串行的时序应该没有错， 请问是否还有其它注意事项？串行ad本身是否有设计问题？
[答：]	There will be no issue for a serial interface ADC. Please pay attention to BUSY signal and the MAST/SLAVE mode. If there is an data ready pin or BUSY pin (such as AD7894), you can use it to interrupt DSP (such as ADSP-2185) and let DSP operate in MAST mode. But you should know that some serial ADC (such as AD7490 , AD7680) use SCLK as the sampling clock.
[问：]	100Mbit/s数据/8路合成，最好每路使用采样率为多少为好？
[答：]	You can use AD9433 (12bit 105MSPS),AD9215(10bit 105MSPS), AD9283 (8bit 100MSPS) a single ADC can do it.
[问：]	ADI公司专家:您好!请问模数转换器有用户可以自己编程的吗?如果有的话,有相关的资料吗,可以给我记一份好吗?谢谢您的回答.
[答：]	I am sorry that I do not know what you mean. Some ADC include PGA(AD7730) , some has digital downconverter (AD6652), some even contain 8051MCU (ADuC812, ADuC824, ADuC831), some contain DSP (ADSP-21991, AD74322, AD73460).
[问：]	我们都知道在有ADC的IC设计中，Vref的设计尤其重要，请问Vref设计要注意一些什么？通常怎么解决？
[答：]	Sorry, I just use REF, such as REF195.
[问：]	假设在设计二阶一位sigma-delta调制器中,DAC的参考电压怎么决定?其值大小对整个调制器的性能有什么影响?当电源电压降低时,参考电压应怎么取值?
[答：]	Sorry, You mean IC design? I think an higher VREF will be better.
[问：]	请问：高分辨率A/D系统设计和板卡设计应注意那些问题，如何才能保证A/D的最大转换精度？谢谢！
[答：]	Please pay attention to Grouding, power decouple and shielding.Clock jetter is important for very high speed ADC. Please use lineary LDO such as ADP3335 to do once more regulater, because normally the power supply is switch type in an PC system. The analog power supply should use lineary power supply.
[问：]	请问：可否推鉴高精度（如16位）多路同时采样的A/D转换器件.
[答：]	AD73360 has 6 channel 16 bit ADC.
[问：]	有无将信号放大与A/D做成一体的性能比较好的芯片？
[答：]	Many. Such as AD7730, ADuC824 (24bit ADC with PGA + DAC + 8052MCU + Flash memory).
[问：]	What kind of ADC is AD9288?
[答：]	AD9288 is a Dual 8-Bit, 40 MSPS, 80 MSPS, and 100 MSPS ADC. I think it's pipe line type.Our fastest 18bit SAR ADC (AD7674) is 800KSPS, 16bit SAR ADC (AD7677) is 1MSPS.
[问：]	请问采样速率和转换速度有和必然联系？
[答：]	There is no necessary relative. This is dependent on the converter architecture. For example, the Sigma-Delta ADC may have very high conversion rate (256 times or more) than the sampling rate.
[问：]	串行AD与CPU，最长布线距离有无要求？谢谢
[答：]	This is dependent on the capacitance on the serial bus. If the capacitance influence the clock eage, you should have a buffer there.
[问：]	请问做一个温控系统（51CPU），热电偶测温（两个探头），家用热水器用，采用哪款A/D最经济。
[答：]	Try to used ADuC824/34. This chip has the 8052 core and flash memory and ADC, DAC there. Check it out on the web @ http://www.analog.com
[问：]	请问做一个温控系统（51CPU），热电偶测温（两个探头），家用热水器用，采用哪款A/D最经济。
[答：]	Try to used ADuC824/34. This chip has the 8052 core and flash memory and ADC, DAC there. Check it out on the web @ http://www.analog.com
[问：]	您好,请问未来的数模转换器将向什么样的方向发展呢?
[答：]	Higher speed, lower power consumption and more integarte digital functions.
[问：]	在数字电视上应用的ADC.
[答：]	AD9283/9288. ADV7183/83 the video decoder also can use there.
[问：]	请讲讲AD6645的接地问题。
[答：]	Please contact our local office for more detail.
[问：]	我们公司要做一批热导率测量的仪器要使用什么样的器件性价比较高？
[答：]	You can try AD7782 on your system. You can get the data sheet on the web site @ http://www.analog.com
[问：]	ADI公司的产品相对其它同类产品有何不同？
[答：]	We are provide more precision more broad products selection and advanced
[问：]	请问目前性能最好的ADC能满足哪些技术指标？谢谢！
[答：]	INL, DNL, SFDR, Sampling rate ..etc.
[问：]	您好，我的问题是：为什么ADC配有“启动转换”和“转换结束”信号，而DAC却没有了？
[答：]	The ADC needs to compare with the reference and to get the right digital coe out. For some architectures, like SAR type ADC, you have to wiat untail the comparison finish and read the digital code on the output register that you can read it out without errors. The DAC is doing very simple that that the digital code and convert into analog.
[问：]	请问，ADI的AD转换器中，有否16BIT的西格玛-德尔塔转换器，转换速度有多快？
[答：]	AD9260 is 16 bits Sigma-Delta ADC can up to 2.5MHz.
[问：]	请问，ADI公司是否有快速、低价格的16-BIT △∑转换芯片。
[答：]	AD7723, AD9260 is good candidate for you
[问：]	ADC与DSP配合使用可以提高工作效率，可以把他们做在一起吗？This is dependent on the process. Normally, ADC use like 0.18um or higher process. But DSP maybe used more advanced technology such as 0.11 or 0.13um process. And, if you put the DSP and ADC together, you maybe try to advoid the noise coupling issue and will add some circutry on it. The result is increase the ADC core die area.
[答：]	在高品质无线数字耳麦产品上，ADI有没有较完善的解决方案？
[问：]	SSM2211, SSM2250 and AD8592
[答：]	多路同时采样芯片的应用
[问：]	This chip usually use on the power (V/I) meaurement such as the power line factors or motor control. That you need to simutineous to get the same position of the V and I information on the monitor devices.
[答：]	我的ADC输出的数老是变输入不变
[问：]	This might caused by many things, such as the power supply, the layout and the reference source.
[答：]
[问：]	请问ADI公司Sigma-Delta A/D转换器的最高采样率是多少MHz？在哪里能得到更多的信息？
[答：]	AD9260 is the higest sampling rate sigma-delta ADC. Its speed can up to 2.5MHz. Please visit out web site www.analog.com to get the data sheet.
[问：]	模数转换器(ADC)在便携式CD机和汽车音响上的应用？
[答：]	try AD1871/77.
[问：]	在测试温度的时候，怎样通过模数转换器（ADC）把准确的温度测试出来，并把这些数据传给CPU，进行进一步的处理？谢谢。
[答：]	The best way is use current source
[问：]	模数转换器（ADC）的在高速数据采集系统中对整个系统性能的影响
[答：]	First of all, the ADC clock and the high speed data bus might cause the system noise level increase if you don't have very good isolation. And, the system EMI issue also is another thing you need to considering when you use the high speed ADC there.
[问：]	能否提供介绍各种AD的原理和应用的资料？
[答：]	Please contact our local office.
[问：]	我是做安防器材视像系统的，诸如网络硬盘录像机，摄像监控仪等，目前方案主要有philips以及韩国的方案还有一些台湾的方案，大部分都用TriMedia1300配SAA7114等方式，而且用的是PSOS操作系统，请问你们有知道性价比更好的方案吗
[答：]	Please contact our local office.
[问：]	在设计中采用哪些措施能够提高采集卡的有效位？ 在PC中的采集卡，使用10位的ADC，有效位一般能达到多少？ 多谢
[答：]	You have to consider to use low noise devices on the system. Such as low noise LDOs, Low noise amplifiers. And make sure you don't push the ADC on its highest sampling rate since is will reduce the ENOB(Efficient Number Of Bit).
[问：]	我是做安防器材视像系统的，诸如网络硬盘录像机，摄像监控仪等，目前方案主要有philips以及韩国的方案还有一些台湾的方案，大部分都用TriMedia1300配SAA7114等方式，而且用的是PSOS操作系统，请问你们有知道性价比更好的方案吗
[答：]	We have a solution based on ADSP21535/532 for the MPEG-4 format. If you interested in this products, please contact our local office for more details.
[问：]	高速模数转换器动态参数的定义和测试 ？
[答：]	You can find the dynamic performance in page 23 of the on line seminar. For the definition, you can find from the datasheet of ADC, AD6644 for example. There are also some slides in the on line seminar: page 31 and 32. They explain the definition very clearly. For the test of the dynamic performance, refer to page 24 please.
[问：]	你能简单介绍最新的模数转换技术——流水线技术；阐述其工作原理、性能特点及其优点？
[答：]	You can find this information from page 39 to 41 of the on line seminar presentation. Normally, it has the advantages: Higher resolutions at high-speeds (14-bits/105 MSPS) and Digitize wideband inputs. AD6644 is this type of ADC.
[问：]	请问高速ADC动态参数是如何定义？
[答：]	Normally, the dynamic parameters definition differs from supplier. So, make sure to read the datasheet carefully. Just give some of the frequently used parameters for your reference.Signal-to-Noise-and-Distortion (SINAD): The ratio of the rms signal amplitude (set 1 dB below full scale) to the rms value of the sum of all other spectral components, including harmonics, but excluding dc.Signal-to-Noise Ratio (Without Harmonics): The ratio of the rms signal amplitude (set at 1 dB below full scale) to the rms value of the sum of all other spectral components, excluding the first five harmonics and dc.Spurious-Free Dynamic Range (SFDR): The ratio of the rms signal amplitude to the rms value of the peak spurious spectral component. The peak spurious component may or may not be a harmonic. May be reported in dBc (i.e., degrades as signal level is lowered), or dBFS (always related back to converter full scale).Page 31 and 32 of the presentation explain this very clearly.
[问：]	在考虑采样率不到一百万次采样每秒 (MSPS) 的高精度模数转换器 (ADC) 时可以进行如何的选择？
[答：]	This is decided by the use of the ADC. First, you have to decide the resolution of the ADC according to the SNR and other key parameters. Second, decide how many channels will be used. Third, you have to decide according to the system which type of the interface should be used. Then you can consider the power supply, PCB layout, the package of the part, price, and so on. If you need any support, just send mail to china.support@analog.com, or call 800 810 1742. ADI will be glad to help you select the suitable ADC for you.
[问：]	能否介绍一下在转换中串行接口的时序图
[答：]	We have the ADC with synchronous and asynchronous serial interface. You can find this kind of information very detailed from the datasheet.
[问：]	我用1543，2543比较多，您对这个芯片有什么看法？
[答：]	We don’t have the ADC with these part numbers. I suggest drop it.
[问：]	ADUC831/832的PC机下载程序在ANALOG的WEB上能download吗?
[答：]	Surely, you can download them from our website. The link is: http://www.analog.com/technology/dataConverters/ microconverter/devTools.htmlIf you encounter any problem, send mail to china.support@analog.com, we can send it to you.
[问：]	ADC元器件在电子式电能表中应用，有何优点？
[答：]	We have the part that can be used in the power meters specially. For one phase it is ADE7755, for three phases, you can select ADE7752 and ADE7754.The home of power meter is in the link:http://www.analog.com/technology/dataConverters/ energyMeasurement/energyMeasurementICs.html
[问：]	是否有8通道24位同步采样的ADC,最高采样频率是多少?
[答：]	We don’t have the 8-chan 24-bit ADC. But we have the 6-chan 16-bit ADC that can sample synchronously AD73360, with the max sample rate of 64KSPS.
[问：]	when sampling,will ADC contribute addtional noise to a weightscale system?
[答：]	Yes. The ADC will have the quantilization error internally. No ADC can avoind this. And this is decided by the system requirement. You can select the suitable ADC to get the precision you needed. AD7730, AD7730L, AD7719 and AD7714 are suitable for weighscale system.
[问：]	我想了解ad7714中的效验寄存器是否是无法修改的，因为我修改后，它自己又恢复了原来的值！每次开机后，自效验的数值都不同，变化很大，是什么原因？还有，高速转换A/D怎样去除信号的噪声？
[答：]	On power-up, the AD7714 performs an internal reset which sets the contents of the internal registers to a known state. There are default values loaded to all registers after a power-on or reset. The default values contain nominal calibration coefficients for the calibration registers. However, to ensure correct calibra-tion for the device a calibration routine should be performed after power-up. To get rid of the noise, you have to use the filters before the ADC, properly arrange the PCB layout. You can refer to the materials in the following link: http://www.analog.com/technology/ amplifiersLinear/training/highspeed.html
[问：]	DAC8562在DA选择列表中没有推荐，如何选择推荐的ad,txdac系列中的DA来代替DAC8562
[答：]	DAC8562 is our 12-bit single 5V supply DAC. It can operate under the speed of 25 MHz. You can find the information from the website of ADI: http://www.analog.com/Analog_Root/ productPage/productHome/0,,DAC8562,00.html TxDAC is our DAC with fast speed. If you want to replace it, you can use AD9752. But we won't recommend you to do this.
[问：]	DAC系列的DA和AD系列开头的DA有何不同的地方，如何选取
[答：]	There are no difference between them, it is only a kind of naming type. You can select them according to the requirement of your system. If you need any technical support send mail to china.support@analog.com, we will select the suitable DAC for you.
[问：]	请问12位输出0～3V的DAC如何选择
[答：]	There are a lot of 12-bit 0-3V output DACs provided by ADI, AD5320, AD5321, AD5322, AD5323, AD5324, AD5325, AD5327, AD5328, AD5340 for example. Maybe you have to specifiy its INL, DNL and other requirement to the selection. Then we can limit it to a small scope. If you need any support, just send mail to china.support@analog.com, or call 800 810 1742, we will be very happy to select the suitable DAC for you.
[问：]	模数转换器的最新速率？
[答：]	This is related to the resolution and type of the ADC. For example, AD6645 is the fastest in communication use, it is 105 MSPS 14-bit. You know, ADI is the lead in signal processing. We will provide the high end products in this field. If you need any information, just feel free to contact china.support@analog.com and call 800 810 1742.
[问：]	能否详解一下开关电容逐次逼近A/D转换器个工作原理和转换过程？谢谢！
[答：]	The overall accuracy and linearity of the SAR ADC is determined primarily by the internal DAC. Until recently, most precision SAR ADCs used laser-trimmed thin-film DACs to achieve the desired accuracy and linearity. The thin-film resistor trimming process adds cost, and the thin-film resistor values may be affected when subjected to the mechanical stresses of packaging. For these reasons, switched capacitor (or charge-redistribution) DACs have become popular in newer SAR ADCs. The advantage of the switched capacitor DAC is that the accuracy and linearity is primarily determined by photolithography, which in turn controls the capacitor plate area and the capacitance as well as matching. In addition, small capacitors can be placed in parallel with the main capacitors which can be switched in and out under control of autocalibration routines to achieve high accuracy and linearity without the need for thin-film laser trimming. Temperature tracking between the switched capacitors can be better than 1ppm/ºC, thereby offering a high degree of temperature stability. You can find detailed information from the following link http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html section 8.
[问：]	专家：您好！能简单说说SIGMA-DELTA的原理吗？谢谢！
[答：]	Mainly, there are four technologies used in the Sigma-Delta ADCs, namely oversampling, noise shaping, digital filtering and decimation. You can find the introduction of Sigma-Delta ADC in page 44 to 47 in the on line seminar presentation. Or you can find it in the application provided by ADI, AN-283.
[问：]	AD7416/7417/7418等如何安装,才能保证测量误差小?
[答：]	You can find this information from page 14 "mounting the AD7416" of the datasheet. Try to give it a safe and free space.
[问：]	请问专家，如何以低成本实现模拟地与数字地的分离？
[答：]	Normally, the digital ground and analog ground should be separated in the board, and connect them from one point either in the power supply or some suitable places. If your board is not very complicated, then 2-layer board is enough, all you will have to use at least 4 layers for your PCB. You can place the analog ground and digital ground in the same layer but separate them. Maybe this can save you some money.
[问：]	AD1833与TMS320VC5402通信如何实现同步？AD1833的采样速率与BCLK以及MCLK之间有什么关系？如果我只选用一个信道，那么如何进行设置，该设置与ZeroDetect有什么关系？
[答：]	For the determination of the MCLK, you have to decide the sample rate first, then to decide which interpolation mode to be used. For the synchronization between DSP and AD1833, this is decided by the operational mode AD1833 will be in. If AD1833 is the master, then AD1833 will do it by itself. And DAP can be master also. For this question, refer to page 13 of the datasheet please. There is no need to synchronize between MCLK and BCLK, it will be did in the AD1833. Don't worry about this. If you use only one channel, then mute the rest. You can find the register information from page 10 Table IX. Zero detect is not used for this purpose. You can find its usage in the datasheet "The AD1833 provides individual logic output status indicators when zero data is sent to a channel for 1024 or more consecutive sample periods. relevant register associated with each DAC. This setting is used to attenuate the DAC output." If you need any other information (CD-R, datasheet for example), send mail to china.support@analog.com, or call 800 810 1742 between 8:30 to 17:30, please.
[问：]	请教各位专家，我是一名正在一家公司实习的大学生，我想做一个计算机的接口电路，将力传感器中采集的信息通过A/D转换送到计算机进行处理，要求响应的速度要尽可能的快，而且还要达到最在的准确度；我想请教一下各位专家要用什么型号的A/D转换器？能提供给我它的性能参数吗？如何进行设计才是最理想的？谢谢！
[答：]	This is decided by the requirement to the ADC and which type of sensor you are used.If possible, you can read the datasheet of AD7730. Also, I would like to recommend you read section 4 of the article from the following link: http://www.analog.com/technology/ amplifiersLinear/training/sensorSignal.html
[问：]	I need AN ADC, 8-channel 8bit,low cost,please me some suggestion.
[答：]	Maybe you have to tell us the sample rate of the ADC. Anyway, AD7829 with 2MSPS is recommended. Or you can send mail to china.support@analog.com or call 800 810 1742 to get more information.
[问：]	采样频率为1.5MHz 10bit ADC,请问有何型号的产品可提供？
[答：]	When selecting ADC, resolution is important, at the same time INL, DNL, serial/parallel and power consumption are also important. Maybe you can have a look of AD7470 for your use.