如何評定一顆ADC非線性？丟碼？
[答：Jing]
you can use ADC"s INL and DNL parameter to evaluate the non-linearity and you can also use ENOB parameter to check code loss. Thanks!Generally ENOB releated with ADC"s SNR
[2006-2-28 10:32:08]
[問：吉星]
在差分輸入時，不考慮直流，使用差分放大器和變壓器哪個更好．
[答：Mariah]
Transformer is better for the better noise and distortion performance, especially in very high frequencies.
[2006-2-28 10:32:14]
[問：Jane Yang]
請問應如何處理板級噪聲對于高精度AD的影響？特別是輸入部分的噪聲？
[答：Jing]
This is a good question and it"s very difficult to answer. Generally, You should consider all the input noise derived from sensor/AMP/BUFFER. You can also use a LPF to reduce the input noise. Remember the BGP of AMP should be 100x of ADC"s throughput. Thanks!
[2006-2-28 10:34:30]
[問：石林艷]
AD變換的參考基準源很重要，對模擬供電電源和數字供電電源的要求也很高嗎
[答：Rui]
模擬供電電源，和數字供電電源相對基準源來說，精度要求相對較低，一般情況下用10uF的電容和0.1uF濾波即可。
[2006-2-28 10:34:31]
[問：zcs_1]
請解釋一下，分辨率和轉換精度之間的區別
[答：Mariah]
For conversion accuracy, it involves many aspecs. For example, INL, DNL, offset, gain error.
[2006-2-28 10:34:46]
[問：Leemour]
對不起能否講一下什么是：RAIL TO　RAIL，這個我一直不太明白。
[答：Xiangquan]
軌到軌指輸入軌到軌，或輸出軌到軌，具體指的是輸入信號或者輸出信號的范圍基本接近于電源，譬如電源是+-5V，輸入信號或輸出信號可以達到+-4.9幾V以上
[2006-2-28 10:35:25]
[問：jlwg]
很多種adi的a/d轉換器件都自帶有標準電壓源，請問是使用器件自帶的標準電壓源好還是另外使用獨立的標準電壓源更精確？
另外使用ad7710時，每次轉換信道后的第一次轉換結果是否是有效的？
[答：Troy]
Use an independant reference to get the highest accuracy and lowest temperature drift.? It depends on how much accuracy your application needs over temperature.
[2006-2-28 10:37:14]
[問：xwlcba]
您提到驅動AD的運放增益帶寬積要求大于100倍采樣速率,請問對運放的轉換速率有何具體要求?
[答：Troy]
To get the lowest distortion (THD), we recommend using an amplifier with at least 100x gain-bandwidth product greater than the sample rate.
[2006-2-28 10:39:36]
[問：bly1979m]
本人最近做了一個項目用于精確測量溫度的，就用到了這兩種器件！請推薦幾款貴司產品？并說說它的大概價格是多少？
[答：Jing]
It"s depend on the accuracy of your system requirement. I am pleased to recommend that you can use our ADR421+AD7799. For price, you can check it on our web or consult our distributor according to your volume. Thanks!
[2006-2-28 10:39:40]
[問：guahuahua]
選用AD7788時，能選擇的最適當的參考基準源是哪一款
[答：Mariah]
You can try the software we recommended in the presentation "reference selection wizard". You can download it from the link of http://www.analog.com/Analog_Root/static/techSupport
/designTools/voltageReference/download.html

?
[2006-2-28 10:41:33]
[問：arzhiy]
RC濾波器設計在ADC前就會出現相位漂移的情況，這樣采集到的信號是一個失真的，是這樣的嗎？
[答：Troy]
The RC filter will not add any distortion to the signal.? The RC filter will reduce noise at frequencies higher than its cutoff frequency.? This improves ADC performance because it reduces out-of-band noise to the ADC input.
[2006-2-28 10:44:33]
[問：yz_yjg]
我們的有一個雙信道數字示波器產品，當進行垂直移位時，即施加給AD9288的直流電平改變時，發現發現基中一個信道在LCD屏上的某些區域的基線變粗（這有規律，如每間隔16或32出現），有2mm到8mm左右不等，更換AD9288即可。大多數是其中的一個ADC有問題，我們希望基線在屏幕上移動時（不加信號），掃描基線的不要發生粗細變化，請問是什幺原因？AD9288能完全消除這種現象嗎？
[答：Mariah]
We need to know more details about your circuit. Would you please send your question and schematic in details to china.support@analog.com, and then our engineer will help you on that.
[2006-2-28 10:45:35]
[問：callhxw]
雙極性輸入信號，采用OP轉換為單極性的到ADC，設計時應關注哪些？
[答：Jing]
First , you can select AD8129/AD8130 to realise the function. But this will reduce the ENOB. I suggest you use differential input ADC too. You should consider the noise from the AMP and the GBP of the AMP.You had better to select a high GBP and CMRR and low noise AMP. Thanks!
[2006-2-28 10:45:35]
[問：Jane Yang]
which reference is better: external or on-chip, for high speed (40~105M) and 12~14bit ADC?
[答：Troy]
External references give better initial accuracy and lower drift over temperature.? Using the on-board reference or an external one depends on the accuracy you need in the application.? Generally speaking, the higher the ADC resolution (# of bits), the more likely you will need an external reference.
[2006-2-28 10:46:16]
[問：liu.gy]
1、就ADI的產品而言，請給出“基準電壓源+ADC”的兩種方案：分離與集成 兩個方案的優缺點？
2、運放到ADC之間什幺時候需要加濾波處理？如果加濾波處理，請給出濾波的方式及性能比較？
?
[答：Xiangquan]
1。集成主要帶來方便，但是往往由于工藝的限制往往不能發揮轉換器的最高性能，如果選擇合適的外部參考源，則可以比較好的發揮轉換器的性能
2。運放與AD之間的濾波主要為的是濾除噪聲，抗混迭，以及給ADC的轉換產生的瞬態能量提供緩沖，一般一階RC低通濾波即可，或者對于帶通濾波，可以根據自己的要求進行設計
[2006-2-28 10:46:34]
[問：chenhaifeng]
放大器的PSRR是否與外電路及輸入信號無關？
[答：Haoran]
PSRR主要是電源對信號的影響，與外電路和信號無關
[2006-2-28 10:47:12]
[問：hzluoping]
請問：1）精密ADC的數字地和模擬地的正確接法及對ADC轉換精度的影響？
????? 2）在單片機系統應用時，對精密ADC的啟動和數字信號的輸出的控制
???????? 有何要求？
[答：Jing]
1> you should consider the system current. If the digital current is small, you can seperate digital GND and analog GND and combine them together in one point. If the digital current or noise is very large, you can also look ADC digital GND as analog GND.
2>I don"t know what you mean. Generally ,some of our ADC has hardware start and software start selection.
[2006-2-28 10:48:39]
[問：arzhiy]
常用的RC往往本生噪聲也很大，這樣且不是更加增加了采樣的噪聲？
[答：Haoran]
噪聲主要來源于電阻，實際上在可能的情況下或電路穩定的前提下，盡量增大電容可以提高噪聲性能。
[2006-2-28 10:48:50]
[問：boclandc]
我采用了AD7671,測試8信道的線性電子尺(等效線性電阻),請問有什幺好的多信道切換,我采用了二片MAX4052后面通過AD620做驅動,但是切換至穩定時間需達10uS,在切換速度上非常不理想.不知貴公司有否這樣的方案,使切換速度小于或等于2uS?謝謝!!
[答：Mariah]
ADI has many new mux and switches which has better performance, like ADG121x, ADG13xx and ADG14xx. Also the settling time also depends on your circuit. You can send your schematic and question to china.support@analog.com. Our engineer can analyze your circuit and give out the solution.
[2006-2-28 10:49:42]
[問：ecnanjing_EBY7E]
請問,電壓基準的精度和溫度系數對AD的精度的影響的換算關系是怎樣的?
[答：Haoran]
你可以在今天的資料中找到，并且可以從我們的網站上下載
[2006-2-28 10:50:00]
[問：hzluoping]
模擬地和數字地的接法對ADC影響大，如何作好接地？
[答：Rui]
地的接法一般有兩種，1。把地平面分割為模擬地和數字地，或者一層數字地，一層模擬地，然后共同接到共地點。2。不分割模擬和數字地，使用多點接地。
對于第一種情況，注意數字地層和模擬地層不能重迭。
對于第二種情況，要提供盡量多的接地點。
[2006-2-28 10:50:14]
[問：amatist]
基準源有齊納二極管和帶隙電壓基準等幾種,它們有何優缺點?
[答：Troy]
References built using bandgaps have lower temperature drift, but they are more complicated and more expensive.? Zener references are usually less expensive, but have more noise and may have lower initial accuracy and higher drift over temperature.
[2006-2-28 10:50:22]
[問：amatist]
對電壓基準源的要求主要有那些指標?如何選擇電壓基準源?
[答：Jing]
Intinal accuracy, temperature drift is two of the key factor. You can according to your system error requirement and download our REF+CONVERTER wizard to select the corresponding REF. Thanks!
[2006-2-28 10:50:22]
[問：elmer]
放大信號中出現大的脈沖信號，怎樣去除這個信號？
[答：Haoran]
你可以先在運放前增加低通濾波器。
[2006-2-28 10:51:00]
[問：wzj0713]
pA~mA的高動態低變化速率輸入的信號調理擬使用ADI產品ad8304，現在需咨詢的是如何最小限度的減小引入噪聲（從PCB版圖、工藝和電路處理兩方面）。
[答：Jing]
You can use AD8304 to interface a PIN and converter current to voltage. To minize the input noise, you should select a better PIN--this is the first noise source. Then you should select high accuract resistor and capacitor . Of course, multi layer PCB is better to minize the inout noise.