|
主题:数模混合信号前端的系统分割考虑 |
| 在线问答 |
| [问：45392] |
如何解决DDS输出信号的幅度控制问题，变化相差4倍。 |
| [答：Mariah] |
DDS具有幅度调制功能，可以通过相应幅度控制寄存器来调制幅度。8月25号会有一个DDS的网上研讨会 |
[2003-7-25 10:34:17] |
| [问：17585] |
使用DDS器件，产生的频率从0到工作频率的40%，但幅度的变化太大，什么原因，如何控制 |
| [答：Mariah] |
可能与您后端的滤波器的设计有关。而且您的DDS相关的幅度调制寄存器是否设置正确。 |
[2003-7-25 10:42:11] |
| [问：percy] |
SOC集成数、摸模块与利用单片数、模IC对信号质量有什么区别？那种更好？ |
| [答：Curt] |
Discrete converters can usually provide higher performance than SOC
solutions. There is a performance advantage to be gained by seperating
analog and digital circuitry, but discrete solutions may not fit in the
available space for the application. Integrated mixed signal front ends
like ADI MxFEs can provide the benefits of discrete solutions without the
high development cost of SOC solutions. |
[2003-7-25 10:45:28] |
| [问：lfq_qing] |
主持人，你好，请问A/DC、D/AC在系统连接中数/模信号之间如何隔离？请举例说明。 |
| [答：Wayne] |
Hi, this is a complicated question which can be a book length.
Basically, you need to make sure power supply for digital and analog
signal are through different ways and seperate them by proper distance,
with less cross better; also ground spliting is important. No
matter what you do, for most cases main purpose is to protect analog
signal from digital signal influnce. ADI has some book for system design
concept, here is one book you can download from website:
http://www.analog.com/technology/amplifiersLinear/
training/highspeed.htmlYou
can find the design guide on section 7 of the book. |
[2003-7-25 10:45:46] |
| [问：XIAO
YAO0321] |
请介绍一下系统的智能分割 |
| [答：Wayne] |
系统的智能分割的目的是以低成本实现最高的系统集成, 达到最高的性能指标,
最小的尺寸和最低的功耗. ADI 的 Othello 芯片组就是系统集成的一个很好的例子.
它提高了混合信号电路的集成度, 但并非单片SOC方案. 相比于低集成度的方案,
它可以使GSM手机的尺寸和元件数减小50%. 它是通过提高系统级的集成化实现的,
而不是硅片的集成化. 在集成高性能CMOS模拟电路之前,
首先得根据系统功能分布将电路划分为模拟和数字部分. 但智能系统划分并不是通过简单的模拟和数字功能去分割和优化以达到它们的技术要求,
从而提高模拟电路的集成度的. 所谓“智能”是指它还要将一部分数字电路集成到混合信号IC, 以提高模拟电路功能区的性能. |
[2003-7-25 10:48:14] |
| [问：hans.xie] |
请问:前端的系统分割的出发点是什么? |
| [答：Eagle] |
ADI的智能划分方法是基于IC设计的技术和成本核算而制定的. 对于混合信号IC, 随着工艺尺寸的减小, 实际上功能、成本和功耗都可能增大.
而电源电压降低（减小）则会导致性能下降. 结果是, 工艺减小带来的成本下降不是非常有效, 可能还赶不上可能的数字IC成本下降.
若是设计片上系统ASIC, 则必须认真权衡(考虑)数字部分工艺的尺寸与混合信号性能之间的利弊(权衡). |
[2003-7-25 10:48:37] |
| [问：XIAOYAO0321] |
请详细介绍一下系统的智能分割 |
| [答：Eagle] |
Please read the seminar materials and listen to the audio,
thanks! |
[2003-7-25 10:49:28] |
| [问：lixiuxue] |
可否推荐适合于声发射信号采集的高精度可变增益放大器，可编程滤波器，以及模数转换器？ |
| [答：Mariah] |
ADI没有可编程滤波器，对于可变增益放大器，你可以考虑AD60x的产品，对于模数转换器，不知道您的具体要求是什么？ |
[2003-7-25 10:56:13] |
| [问：jiaxueqin] |
在无线接收系统中，模拟的前端存在着相位不稳，稳定性差的缺点，而数字接收就可以很好的解决这一问题。但是数字接收就存在着要求采样率高的问题，这一矛盾怎么解决呢？ |
| [答：LiaoWS] |
ADI will try to solve these questions. And ADI can provide more and
more high speed ADCs and DACs, DDC, DUC and DSPs. |
[2003-7-25 10:57:38] |
| [问：change] |
请给汽车电子前段信号抗干扰及EMC处理方案 |
| [答：Wayne] |
Most important is "shielding" of signal routine, also power supply
de-coupling to drop interference should be taken care of. Auto-electronics
is a very interesting field, you can call 800-810-1742 to our China
support center, we"ll be glad to discuss details with you. However, in the
section 7 of below PDF book you can find some helpful ideas:
http://www.analog.com/technology/
amplifiersLinear/training/highspeed.html |
[2003-7-25 10:57:40] |
| [问：ljp] |
模拟前端的接口电平应如何考虑?有何具体要求? |
| [答：LiaoWS] |
This is decided by your system design. For wireless system, you can
calculate this according to the NF reuirement. |
[2003-7-25 10:58:42] |
| [问：xzzss] |
ad73360的供电电压多少为最好，3V还是3.3V，如果用3.3V的话，会不会对ad73360的采样结果有影响。ad73360的内部参考输出电压正常情况下的偏差有多少？AD21992的参考输出电压的正常偏差有多少？这两种片子我是用内部参考电压好还是外部参考电压好一些呢？ |
| [答：Eagle] |
Both 3V and 3.3V is OK for AD73360, if you use an LDO such as ADP3335
will be better. The AD73360 reference is a bandgap reference that
provides a low noise,temperature-compensated reference to the ADC. Min is
1.125V, Typ 1.25V, MAX 1.375V.ADSP-21992 Min 0.94V, Typ 0.98V, MAX
1.02V.You can use an external voltage reference if you need higher
performance. ADR421 B grade Min 2.499V, Typ 2.500V MAX 2.501V. |
[2003-7-25 10:58:54] |
| [问：zjx-a] |
为什么有些"轨对轨"的运算放大器输出信号幅度只有电源电压的一半就开始失真? |
| [答：Mariah] |
这应该与你增益的设置，放大器的带宽等指标有关系 |
[2003-7-25 10:58:55] |
| [问：jiaxueqin] |
不同芯片的不同工作电压之间的兼容性能够很容易的解决吗？ |
| [答：LiaoWS] |
This is decided by the parts. And you should try to select the parts
with fewer voltages. |
[2003-7-25 10:59:32] |
| [问：03844] |
这里所说的系统分割是指在PCB布局上的考虑么？ |
| [答：LiaoWS] |
No, this is the system partition according to the TTM and cost and
performance. |
[2003-7-25 11:00:05] |
| [问：qin] |
如何避免模拟和数字信号的相互干扰? |
| [答：LiaoWS] |
Use the sepeate analog and digital ground and try to decoupling the
power suppliers. |
[2003-7-25 11:01:24] |
| [问：reinaci] |
如何尽量减少采样时钟对模拟信号的影响? |
| [答：Curt] |
It is important to isolate the clock signal path from both analog and
digital signal corruption. This is particularly important in
cases of high frequency signals. This is typically done by 1.
spacing signals as far apart as possible, 2. maintaining a clean analog
reference plane for the clock and analog circuitry and observe best
possible layout practices, and 3, placing grounded shields around the
signals. |
[2003-7-25 11:01:46] |
| [问：zjx-a] |
光电接收器是否有信噪比指标,怎样测试?需要什么测试设备?PIN光电接收器的线性工作区在第几限相? |
| [答：LiaoWS] |
OK. You can raise this question to china.support@analog.com. We will
help you on this. |
[2003-7-25 11:03:02] |
| [问：yinyz] |
1,请谈谈DC-servo的原理及ADI的实现2，我们设计光电探测器的放大电路时遇到了厂家不能提供SPICE模型的问题，你们如何解决光电放大的仿真问题？ |
| [答：Mariah] |
您是指的是ADI的哪个系列的产品？应用于什么领域？您可以找到一些SPICE模型在下面的链接。
http://www.analog.com/Analog_Root/sitePage/
mainSectionResource/0,2131,level4%253D%
25252D1%2526level1%253D150%2526level2
%253D%25252D1%2526level3%253D%25252D1%
2526resourceWebLawID%253D26,00.html |
[2003-7-25 11:03:08] |
| [问：mol] |
请问数模信号地应分别怎样处理？ |
| [答：Wayne] |
By one word, for system: seperate then joint at one point; for mixed
signal IC like ADC/DAC, take it as analog IC with single ground (analog).
Details you can refer to page 7-27 to 7-30 of section 7 of below PDF book:
http://www.analog.com/technology/amplifiersLinear/
training/highspeed.html |
[2003-7-25 11:03:08] |
| [问：xzzss] |
我用的时AD73360来进行数据采样，我板子上还用到了ad21992，我采样出来的0电压波形会有些脉冲出现，值不是多大，我想知道大概是那些原因可能引起这类现象，如何能比较好的避免这类现象的出现，在PCB布局时要注意那些，如何能更好的模拟信号受到数字信号的干扰？ |
| [答：Eagle] |
1. Try to use LDO (ADP333x) instead switch power supply. Maybe switch
noise cause it.2. Seperate Analog Ground Plane with Digital Ground
Plane, connect in one point.3. Use different power (or use Bead), add
0.1uF CAP decouple every power supply pin.4. Try use differencial
input.5. At least use 4 layer PCB.Please refer to some PCB layout
article or contact us directly. |
[2003-7-25 11:03:27] |
| [问：12345] |
请问公司有用于监控4通道输入一输出的芯片吗 |
| [答：LiaoWS] |
What"s the input and output of the signal? Is it power
supply? |
[2003-7-25 11:04:24] |
| [问：lfq_qing] |
主持人：你好，请问模拟数字整合系统中的隔离问题如何解决？请示例。 |
| [答：LiaoWS] |
You can use the ADuM1100, ADuM130X and ADuM140X as the digital
isolators. |
[2003-7-25 11:05:49] |
| [问：35649] |
What"s TTM? |
| [答：LiaoWS] |
Time to market |
[2003-7-25 11:08:03] |
| [问：zjx-a] |
怎样设计带有直流电位的交流信号放大电路? |
| [答：Wayne] |
If you want to reject common voltage, you can use differential amp,
instrument is prefered specially for high CMRR, or sometime very high
common voltage. For example, AD629 can do that for common voltage as
+/-270v.If you just want to reject DC voltage, using a capacitor
before amp can help easily. |
[2003-7-25 11:08:25] |
| [问：samire] |
如何处理传感器的微弱信号?是否需要屏蔽以防止干扰?还有别的好办公吗? |
| [答：Mariah] |
关于传感器的微弱信号，我们有专门的一个文章介绍如何进行信号调理。请参考以下链接http://www.analog.com/technology/amplifiersLinear/
training/sensorSignal.html |
[2003-7-25 11:09:29] |
| [问：xzzss] |
在ad73360前端，要采样的信号除了经过RC滤波，还要加采保报和运放吗，它内部的功能能不能不要像别的芯片那样呢？ |
| [答：Eagle] |
No need, it has signal PGA in it. |
[2003-7-25 11:09:37] |
| [问：nskang] |
最关心前端模拟弱信号的选频放大与调理电路 |
| [答：LiaoWS] |
Whhere the signal conditioning will be used? If used in the wireless
system, try to select the parts with better NF and higher gain. |
[2003-7-25 11:10:27] |
| [问：sxbh] |
我现在在做一个设计，牵涉到工频5次谐波分量百分白的测量，不知贵公司有无相关集成电路可以采用？ |
| [答：Eagle] |
We have customers succeed in use OP2177 + AD73360 +
ADSP-2191. |
[2003-7-25 11:10:51] |
| [问：samire] |
模拟电路少不了基准电压源，如何减少对他的影响？ |
| [答：LiaoWS] |
Treat it as the analog signal. And protect it. Take are of the
grounding and power decoupling. |
[2003-7-25 11:12:04] |
| [问：song
hengli] |
如何解决前放的漂移和失调？ |
| [答：LiaoWS] |
Where the parts will be used? What"s the bandwidth? You can use
chopper amplifiers, AD8551, AD8571 for example. Another way is to
calibrate it in your system software. |
[2003-7-25 11:13:30] |
| [问：deguiqin] |
数字地和模拟地是否需要分开？如何在连接到一起呢？ |
| [答：Wayne] |
For system, ground should be seperated into analog/digital; bur
specially for mixed signal IC like ADC/DAC, you should take it as analog
IC with analog ground. Details you can refer to page 7-27 to 7-30 of
section 7 of below PDF
book:http://www.analog.com/technology/amplifiersLinear/
training/highspeed.html |
[2003-7-25 11:13:50] |
| [问：ljp] |
ADI公司有无关于模拟和数字分割的仿真系统可以用来设计? |
| [答：LiaoWS] |
No, no company will provide that to you. Maybe you can use VHDL to
implement it. But we are not sure whether this is accurate
enough. |
[2003-7-25 11:14:25] |
| [问：lfq_qing] |
请问能否对AD7701的输出进行解释，我现在在异步传输UART的方式下，只能做到4K
bount rate,请问能否更高一些。 |
| [答：Mariah] |
AD7701的输出速率为4K，可以用高于4K的速率来读取数据 |
[2003-7-25 11:15:36] |
| [问：alexie] |
我有一个检测装置：1。通过一个摄像头摄进来视频信号；2。通过一个传感器来检测一个运动设备到摄像头的距离（已经把他转化成了数字信号）。然后我想把这二种信号混合，在带视频口的显示器上显示。具体可以表现为在在显示器的右上角显示如下信息：“二者距离为：xx米”请问各位老师：1。怎么来实现这个检测装置；2.假设有多路信号（数字）混合呢？3.可以在显示器的任意位置实现吗？谢谢！ |
| [答：Eagle] |
You can use ADV7183A video decoder to convert you video into digital
(ITU-R BT.656), then use ADSP-BF532 to process it. The distance from the
sensor can be input for the PPI or SPI to DSP. THen you need and ADV7171
video decoder to get R/G/B to VGA, or Video to CRT monitor. |
[2003-7-25 11:16:01] |
| [问：bslk5] |
请问对于混合信号，线路板的设计是地线分开还是模拟和数字完全分开，最后再统一地线，那个抗干扰性最强 |
| [答：Wayne] |
For mixed signal circuit, normally you should use single ground
(analog). Please refer to previous answer to same question. |
[2003-7-25 11:17:21] |
| [问：ljp] |
详细分割能否给出STB中的考虑来提高灵敏度和减少干扰? |
| [答：Eagle] |
Normall the digital ASIC or CPU have big power. Seperate the
Analog/Digital mixed front end (AFE) can minimize the interface from the
digital noise. THen higher SNR, higher sensitivity. |
[2003-7-25 11:18:43] |
| [问：猫王] |
实验测试下来AD73360的线性度不好,如何处理? |
| [答：Eagle] |
Calibrate with software. |
[2003-7-25 11:19:12] |
| [问：hans.xie] |
Eagle,each MxFE is designed to special
solution,does it mean s if I use it to other will waste parts
of the function and the cost will be high? |
| [答：Curt] |
While its true that MxFEs are targeted at specific functions, they are
designed to be flexible. By designing them for multiple functions, the
volume is high, so the cost is low. The pricing of MxFEs is designed so
that even if not all functions are used, they are still the most cost
effective solution. |
[2003-7-25 11:19:22] |
| [问：33995] |
能否进一步解释一下“系统级的集成化”和“硅片的集成化” |
| [答：Mariah] |
硅片的集成化指的无论模拟还是数字部分都尽量集成在芯片上，而系统级的集成化是指在一系统的概念下对各个部分进行优化并集成。 |
[2003-7-25 11:21:02] |
| [问：ecnan
jing_EBY7E] |
专家你好！我正在使用AD73360进行六路信号的采集工作，发现我的程序进行16点数据采集还没有问题，进行128点的时候就不行了。采样速率我已经设置为最大值，还是不行。所以我想问一下，进行128点六路同时采集有没有什么需要特别注意的地方？麻烦你给我讲一讲。谢谢了。 |
| [答：Eagle] |
AD73360 can run 64 kS/s Maximum Sample Rate. If you really need high
speed, then you need use SAR ADC such as AD766x. |
[2003-7-25 11:21:38] |
| [问：heguangju] |
1、模拟地和数字地是在电路板上汇合还是在电源输出点汇合好？2、模拟和数字分割后，跨越分割区的信号如何受到影响？ |
| [答：Wayne] |
1. I think you"re asking about system (multi-PCB), then joint point
should be at power supply.2. The signal routine will be influenced by
analog/digital spliting, therefore you need to make sure, especially
digital signal routine will not cross analog signal routine to damage its
quality. |
[2003-7-25 11:22:09] |
| [问：song
hengli] |
ADI公司有无模拟通道隔离的AD？有没有免费样品？ |
| [答：LiaoWS] |
ADI has the ADC that has more than one ADCs in it. For the free
samples, please go to www.analog.com to get it. |
[2003-7-25 11:22:30] |
| [问：45392] |
对于ADC/DAC，其模拟电源和数字电源的设计 |
| [答：Wayne] |
Please refer to the answer to same questions previously. |
[2003-7-25 11:23:13] |
| [问：73699] |
使用9862 常出现的错误请举出2例 |
| [答：LiaoWS] |
We have not encountered problems in using AD9862. Feel free to use it,
and we can provide technical support locally. The toll-free number 800 810
is one way for you. |
[2003-7-25 11:23:36] |
| [问：scien
ceMode] |
模拟信号处理的采样保持的主要原理是怎样的？ |
| [答：Mariah] |
首先对信号进行采样，使信号建立并稳定，然后利用开关切换到保持方式进行模数的转换。 |
[2003-7-25 11:24:58] |
| [问：samire] |
模拟电路是否也会对时钟的抖动有影响? |
| [答：LiaoWS] |
low frequency analog signal won"t infulence the clock. What will be
enountered frequqntly is that the clock influence the analog
signal. |
[2003-7-25 11:25:19] |
| [问：35649] |
How many ways to partition the
modules? |
| [答：Eagle] |
To achieve highest performance/price, one analog/digital mixed front
(AFE) and one high density digital ASIC is perfered. Sometimes power
management is also intergated into digital ASIC. But normally the Audio is
not intergated in Video, because the line width is different. |
[2003-7-25 11:26:18] |
| [问：jiaxueqin] |
MxFE适合用于窄带系统吗？ |
| [答：LiaoWS] |
What"s the bandwidth? We have mentioned in the presentation that when
the ADCs and DACs can be used, you can use it. |
[2003-7-25 11:27:51] |
| [问：ljp] |
多层PCB中如何布置模拟和数字器件?模拟和数字的接口如何处理较好? |
| [答：Wayne] |
At first, seperate the ground of every single PCB, place digital and
analog devices seperatly, but use back-to-back Schottky diodes to connect
the ground on board. Meanwhile, connect digital for all PCBs together,
connect analog ground for all PCBs together. Finally all ground connect at
power supply site.Please refer to Figure 7.26 of below PDF
book:http://www.analog.com/technology/
amplifiersLinear/training/highspeed.html |
[2003-7-25 11:28:13] |
| [问：qin] |
系统分割中的四种选择,目前用得最多最普遍的是那种?在PCB设计和布局中如何实现? |
| [答：Curt] |
Historically there has been a push to single chip SOC integration, as
process geometries continue to shrink, this is starting to change. It is
no longer cost effective to integrate complete systems, development cost
and design risk are very high for mixed signal ICs as process geometry
shrinks. Single chip SOCs are even riskier. As a result, there is a shift
toward smart partitioing where mixed signal technology is implemented on
its optimal technology and VLSI digital circuits are put on the smallest
process possible. Greater analog integration is possible when seperating
analog and digital, which can increase total integration even if the
number of ICs increases. PCBs have always seperated analog and digtal to
maintain signal integrity, with MxFEs the layout is simplified, the MxFE
can be located as a bridge between the two sections. |
[2003-7-25 11:28:38] |
| [问：zhy1688] |
我正在做一个100万倍的放大器，对第一级放大器的要求很高，请问用AD的哪一种放大器可以实现？ |
| [答：Mariah] |
您可以使用我们精密运算放大器。选择偏置和漂移相对较低的运算放大器。对于放大倍数较高的精密放大器，您可以考虑我们的仪表放大器AD620,AD623等。 |
[2003-7-25 11:29:14] |
| [问：qin] |
如何验证或仿真分割的正确性和有效性? |
| [答：LiaoWS] |
There are four ways. The effection and whether it is correct should be
based on the time to market, performance and cost. Four ways are suitable,
but you should choose the better one. |
[2003-7-25 11:29:33] |
| [问：jiaxueqin] |
为了获得更好的效果通常是将模拟的前端尽量压缩，而用数字处理来实现。请问如何高效的实现？ |
| [答：Wayne] |
This is just a system-partition concept. As you can see from this
seminar, every partition manner has its advantage, it"s depending on your
preference: performance ? cost ? It"s also depending on your product
background: fixed standard ? high volume ?You can refer to the
introduction of this seminar. |
[2003-7-25 11:31:26] |
| [问：ecnan
jing_EBY7E] |
在遥感遥测信号采集时，输入常为极其微弱信号。请问AD有无带宽为20MHz的弱信号放大器？ |
| [答：Mariah] |
你可以考虑AD797，AD8610 |
[2003-7-25 11:32:15] |
| [问：lfq_qing] |
欠采样技术是何时开始采用的？ |
| [答：LiaoWS] |
It is widely used in wireless systems. And ADI is the leader in this
field. AD9240, AD6644/5, AD9244 are the best examples for this. |
[2003-7-25 11:32:25] |
| [问：xzzss] |
问个不太相关的问题：我用AD2191来控制液晶显示的话，和一般的单片机控制有什么区别，要注意那些事情？谢谢！！ |
| [答：LiaoWS] |
Please send mail to china.dsp@analog.com, or call the toll-free number
800 810 1742. They will help you on this. |
[2003-7-25 11:33:18] |
| [问：lfq_qing] |
运放的漂移和精度在系统中如何解决？ |
| [答：Mariah] |
选取漂移和精度较高的运算放大器，您可以考虑ADI的精密放大器，请参考我们的运放的解决方案通报，在我们的网站上可以找到 |
[2003-7-25 11:33:31] |
| [问：lfq_qing] |
请问模数转换中，转换精度与地信号有没有决定性的关系，如有，怎样处理？ |
| [答：Wayne] |
It"s has very important influence on resolution. therefore you need to
make sure grounding is very proper (you can refer to the answer to same
questin previously); also you can use some devices like instrument which
can help you reject grounding noise, like AD8221,
AD620/623/629...... |
[2003-7-25 11:33:43] |
| [问：zhy1688] |
我现在做一个100万倍的音频放大器，带宽在100Hz~1.6KHz左右，采用多级放大，要求第一级放大器高增益，而且具有很低的噪声系数。请问各位老师：1.这种放大器能不能用通用的放大器（运算放大器或仪表放大器）实现？2.AD公司有那些器件适合做该放大器的第一级？谢谢！ |
| [答：Mariah] |
ADI的仪表放大器应该可以满足您的要求。 |
[2003-7-25 11:34:41] |
| [问：scien
ceMode] |
数字信号同模拟信号的分割的主要依据什么？ |
| [答：Wayne] |
For most cases it"s depending on "digital signal will not damage
analog signal".Please refer to previous questions for
details. |
[2003-7-25 11:34:49] |
| [问：ljp] |
系统分割如何把速度考虑在内? |
| [答：Curt] |
One of the benefits of smart partitioning with MxFE"s is that they are
designed to keep interface speeds low. For example,
interpolation filters are designed into MxFEs and can be used to reduce
the digital data interface rate while keeping the update rate
high. Similarly, decimation filters can be used with
ADCs to maintain high sample rates and reduce digital interface data
rates. |
[2003-7-25 11:36:10] |
| [问：yetoo] |
AD9863相对9860有何改进? |
| [答：Eagle] |
AD9860: AFE for MMDS, MDS, LMDS, LMCS, 2 10 Bit 64MSPS A/D for Direct
IF, 2 Aux 10 Bit A/D"s @ 1.25MSPS, with on chip 128MHz DDS 12 Bit Digital
UpConverter Output BW =DC>65MHz, prgm. PLL Clock Multiplier, Vsys=3V @
388mA, w/2x or 4x Upsampling Interpolation LPF & 4 Aux 12 Bit
D/A"s.AD9863: Dual A/D: 12 Bit. 50/80MSPS, Dual D/A: 12 Bits 200MSPS
w/1/2/4x Interpolation Filter, Vsys=+3V @ 160mA, w/Internal PPL and Timing
Generator.AD9863 Receive path includes Dual 12 Bit Analog to Digital
converters with Internal or External Reference, 50 and 80 MSPS versions;
Transmit path includes Dual 12 Bit, 200 MSPS digital to Analog converters
with 1x, 2x or 4x Interpolation filters and TxPGA Control; Internal Clock
Distribution Block including a Programmable Phase-Locked-Loop and timing
Generation circuitry allow for single reference clock operation. |
[2003-7-25 11:36:21] |
| [问：liu1875] |
在GPS中，前端的低噪声放大器不知道贵公司有什么样的产品？ |
| [答：LiaoWS] |
We have the GPS total solution. Please contact ADI for detailed
information, you can call the toll-free number 800 810 1742, or write to
china.support@analog.com |
[2003-7-25 11:37:00] |
| [问：samire] |
模拟电源的低通滤波器如何设计?通带的宽度有什么来确定?阻带衰耗多大合适?
|
| [答：Wayne] |
Normally it"s not filter for power supply, but only de-coupling with
like capacitors. If you"re using single supply for both analog and digital
circuit, then please use ferrite-bead between digital and analog power
supply pin of the IC. |
[2003-7-25 11:37:29] |
| [问：kun
lunhuang] |
能不能说一下在PCB layout
时模拟和数字信号的一般布放原则，在你们的网站上什么地方可以找到相关的资料？ |
| [答：Wayne] |
Please refer to section 7 of
:http://www.analog.com/technology/amplifiersLinear/
training/highspeed.html |
[2003-7-25 11:38:19] |
| [问：lixiuxue] |
或者说请推荐声发射信号采集的模拟前端解决方案。 |
| [答：Mariah] |
您可以把您的具体设计考虑告诉我们通过8008101742免费技术支持电话或者写信到china.support@analog.com |
[2003-7-25 11:38:44] |
| [问：ecnan
jing_EBY7E] |
前级放大器（3G应用），有无增益可编程控制的？ |
| [答：LiaoWS] |
Of course, ADI have a lot of RF VGAs, ADL5330 for example. You can
contact the toll-free number 800 810 1742 for more detailed information or
write to china.support@analog.com |
[2003-7-25 11:40:35] |
| [问：yetoo] |
随着便携式系统和混合电平器件的增加，为了降低功耗、分离模拟地和数字地、减少PCB层数，PCB设计中大量采用了地电平面的分割。但是，地电平面的分割会导致共模噪声的增加,请问如何可以减少EMI噪声? |
| [答：Wayne] |
Your question is not so clear, however, ground spliting can help to
decrease grounding noise i/o increase it.For common noise like
grounding noise, you can use differential amp to reject noise; for EMI,
"shielding" is a good way, but proper devices placement can help as
well. |
[2003-7-25 11:41:32] |
| [问：LKLYP] |
AD放大器产品目前有那些种类？ |
| [答：Mariah] |
ADI的放大器有很多种类，像电流反馈型和电压反馈型的告诉运放，仪表放大器，各种精密放大器，斩波放大器，隔离放大器等等，具体
的请登陆我们的网站。 |
[2003-7-25 11:41:54] |
| [问：lfq_qing] |
请问ADI有没有百兆级的混频器？请说明型号？ |
| [答：LiaoWS] |
AD8343. Please go to the www.analog.com to download its
datasheet |
[2003-7-25 11:41:58] |
| [问：17585] |
AD9851有幅度调制寄存器吗？ |
| [答：Mariah] |
AD9851没有幅度调制寄存器 |
[2003-7-25 11:44:43] |
| [问：samire] |
模拟电路少不了基准电压源,如何减少对它的干扰? |
| [答：Wayne] |
Please make sure no big noise signal like digital signal pass its
routing. Other thing need take care includes grounding, power supply
de-coupling, and sometimes even shielding. |
[2003-7-25 11:44:45] |
| [问：alexie] |
各位专家你好： 针对alexie提出的检测装置能否提供一个参考设计？ 谢谢！ |
| [答：LiaoWS] |
Would you please contact ADI via the toll-free number 800 810 1742
after the seminar? |
[2003-7-25 11:44:47] |
| [问：xue
meizhao] |
能否详细叙述一下验证或仿真分割的正确性和有效性的四中方法 |
| [答：Curt] |
Generally speaking, unless volume is extremely high and changes are
extremely unlikely, smart partioning is the lowest cost solution. This is
especially true when analog performance is important. Integrated SOC
solutions have very high development cost and limited analog performance.
In addition there is a high risk of having to do multiple design
iterations to get acceptable performance. With fine geometry processes,
this is very expensive. In addition, designs that have significant analog
performance requirements can be much more higly integrated with smart
partitioning than with any other option. MxFEs are so cost effective that
they are the lowest cost even if not all functions on a chip are being
used. |
[2003-7-25 11:44:51] |
| [问：icesoar] |
这种MxFE主要用在哪一个领域最合适？谢谢 |
| [答：Eagle] |
AD986x: Communications/MxFE: Modem, Cable/Set/Top Box. AD9860/2:
AFE for MMDS, MDS, LMDS, LMCSAD9861: Portable application due to lower
power consumption.AD9860/2 can also be use as all kind of
wireless transceiver, for example, use AD8347 or AD8348
demodulator and use AD8345/6/9 modulator, it"s easy to design satellite
receiver or Pico Cell Base Station. |
[2003-7-25 11:45:33] |
| [问：ecnan
jing_EBY7E] |
MxFE的内置滤波器是用什么方式实现的？使用时是否要外交部LC？ |
| [答：LiaoWS] |
The integrated filter are digital filters. No external LC will be
needed. You can refer to the datasheets of them www.analog.com |
[2003-7-25 11:45:56] |
| [问：lfq_qing] |
模数转换模拟输入如何解决负载电容的问题？ |
| [答：Wayne] |
If necessary, please add an extra amplifier before the ADC. |
[2003-7-25 11:46:42] |
| [问：samire] |
分割中对增益和动态范围有何考虑?动态范围要留有多大的富余度? |
| [答：LiaoWS] |
This is decided by the system requirement. If you want to discuss
this, please call 800 810 1742 after the seminar. |
[2003-7-25 11:47:14] |
| [问：03844] |
请问这个前端是什么意思啊？是指缓冲和预处理么？谢谢 |
| [答：Eagle] |
指ADC和DAC，包括某些辅助功能，如时钟，控制增益用辅助DAC和检测状态用辅助ADC。 |
[2003-7-25 11:47:31] |
| [问：ljp] |
系统分割中的模拟电源和数字电源如何考虑?两者之间是否要加滤波?滤波器如何设计? |
| [答：Wayne] |
You"d better use seperate power supply. But for some cases, it"s
permitted to use single for both analog and digital, then a ferrite-bead
between them is ok. |
[2003-7-25 11:47:50] |
| [问：ecnan
jing_EBY7E] |
MxFE是否包含PLL? |
| [答：LiaoWS] |
Some MxFE has the PLL, but the clock cannot be used externally. For
example, AD9861 has it. All these information can be got from their
datasheets. |
[2003-7-25 11:48:42] |
| [问：alexie] |
ADV7183A VIDEO 和ADSO-BF532及ADV7171 VIDEO
DECODER这三种的芯片资料和典型的应运、原理图（或者DEMO）在哪里能找到？谢谢！ |
| [答：Eagle] |
Please contact 800 810 1742 or email to
china.support@analog.com |
[2003-7-25 11:48:45] |
| [问：peng-kai] |
请问： ADI公司针对微弱的模拟信号（如生理电信号等）处理中，要求低噪声、高放大倍数、低漂移等。前置放大、中放、功率放大等，有没有具体的方案提供，及相关参数的评价等。谢谢！ |
| [答：Mariah] |
ADI
对于微弱信号有许多放大器可供您选择，像我们一些精密放大器，斩波放大器和仪表放大器等，它们的偏置、漂移和噪声指标请登陆我们的网站。 |
[2003-7-25 11:48:59] |
| [问：thomson] |
对高速采样的AD73360，在EMC上有何建议， |
| [答：Eagle] |
It"s seems that you need call 800 810 1742 to discuss. |
[2003-7-25 11:49:55] |
| [问：xingyihu] |
请告诉智能划分及MxFE资料处 |
| [答：LiaoWS] |
Please contact ChinaEcnet or write to
china.support@analog.com |
[2003-7-25 11:50:37] |
| [问：liu1875] |
在芯片上模拟的电流源要经过数字部分，这在版图上要注意些什么？ |
| [答：Wayne] |
Basically it"s not permitted for analog power supply to pass digital
circuit. If it can"t be avoided, then please try to seperate its routine
from digital section by some area cutting. |
[2003-7-25 11:51:05] |
| [问：samire] |
怎样考虑电源、地平面的铺设来减少对模拟电路的噪声影响? |
| [答：Wayne] |
Please refer to previous answers. |
[2003-7-25 11:51:22] |
| [问：qin] |
能否给出PCB中模拟和数字信号的布线设计一般规则? |
| [答：Wayne] |
Please refer to previous questions and answers. |
[2003-7-25 11:52:48] |
| [问：17585] |
何种DDS有幅度调制控制器？ |
| [答：Mariah] |
AD9852,AD9854,AD995x。In fact,for AD9851 you can adjust the
amplitude by the Rset which can set the full scale value.On August
25th there will be a net seminar of DDS. Welcome to it. |
[2003-7-25 11:55:39] |
| [问：ecnan
jing_EBY7E] |
专家演讲时提到宽带ADC,请问带宽能到多少？ |
| [答：LiaoWS] |
This is decided by the ADC, please refer to the datasheet of them. And
normally, the bandwidth is decided by the SHA in the ADC. |
[2003-7-25 11:56:08] |
| [问：percy] |
混合使用IC集成系统和使用SOC集成系统成本上好像还是有很大差异，比如使用内置的TV－encoder和外部的TVencoder之间就有可观的成本。有否一个可行的计算方法，考虑这个成本？ |
| [答：Wayne] |
When we talked today about system partition, we mainly focus on AFE.
You question is a little different from this topic. Basically, using
internal encoder can be cost effective (but depending on application
market data, like volume, technology mature status), however, seperate
encoder is necessary for performance consideration. You can still refer to
some data in this seminar (IC design, manufacturing, marketing mature
status......) for cost evaluation. |
[2003-7-25 11:57:19] |
| [问：heguangju] |
不同频率的模拟信号需要地线分割吗? |
| [答：Wayne] |
It"s a concept of "shielding" with grounding line. For high frequency
signal it"s necessary. |
[2003-7-25 11:58:20] |
| [问：huangyg] |
在AD转换中，参考电压能不能大于供电电压? |
| [答：Eagle] |
Most part can not, but some can. For example,
AD7943/AD7945/AD7948: +3.3 V/+5 V Multiplying 12-Bit DACs. VDD = +4.5
V to +5.5 V; VREF = +10 V.Normally use can use an higer
external voltage refence to extend the inner voltage referece. For
example, You can use ADR423 (3v) to extern the 2.5V inner voltage referenc
in ADuC832 (8 channel 12bit ADC, 2 ch DAC, 8052 MUC, 62k Flash
memory). |
[2003-7-25 12:00:12] |
| [问：35649] |
What"s the goldedn rule for signal shielding
based on frequency? |
| [答：Mariah] |
Please notice the seperation of analog circuit and digital circuit.
Please notice the power supply and ground design. For high frequency
design,please use shielder. |
[2003-7-25 12:01:05] |
| [问：lijin_as] |
在模拟电源地处把数字地和模拟地连接和在ADC处连接，那个方案更好一些？ |
| [答：Wayne] |
Please refer to previous questions and answers.You can refer to
some books you can download from ADI
website:http://www.analog.com/technology/amplifiersLinear/
training/highspeed.html
http://www.analog.com/technology/amplifiersLinear/
training/sensorSignal.html
http://www.analog.com/technology/dataConverters/
adc/standard/adc_matrix.html Also,
you can send email to china.support@analog.comor call
800-810-1742for technical support. |
[2003-7-25 12:01:21] |
| [问：17585] |
AD9851控制幅度输出有何方案？ |
| [答：Mariah] |
You can adjust the Rset. You can select our digital potentiometer as
the Rset. |
[2003-7-25 12:02:07] |
| [问：samire] |
分割中是否主要考虑数字信号对模拟信号的影响?或者是两者的相互影响? |
| [答：Eagle] |
这是其中一方面，另外一方面是考虑总体成本和芯片的设计风险。 |
[2003-7-25 12:02:24] |
| [问：zhy1688] |
我用AD620做高增益放大器时不能满足我的要求，请问AD有没有更低噪声系数的高增益放大器？谢谢！ |
| [答：Mariah] |
You can consider AD8330,AD8332 |
[2003-7-25 12:04:51] |
| [问：xue
meizhao] |
当有来自不同仪器的模拟信号需监测时，对这些信号的预处理需注意写什么问题 |
| [答：Eagle] |
主要是抗干扰，如隔离、屏蔽，差分传输等。例如现在流行用AD8129和AD8130差分传输。 |
[2003-7-25 12:05:02] |
中电网官方微博
