| 主题：用于阻抗和电容传感器的先进转换器架构 |
| 在线问答： |
| [问：encaon] |
如何解决传感器信号长线传输所带来的幅度衰减? |
| [答：Yiming] |
You can add an amplifier at the receiver side. |
[2005-8-12 10:42:40] |
| [问：ecnanjing
_EBY7E] |
在工业应用中工频干扰如何解决? |
| [答：Mariah] |
The basic and effective method is filter and shielding. |
[2005-8-12 10:43:07] |
| [问：ahhnsh] |
请问电容传感器应用于报警电路的型号，还有具体的应用文献哪里有参考？谢谢！ |
| [答：Yiming] |
AD7745/6/7. Please visit http://www.analog.com for more information.
Thanks. |
[2005-8-12 10:44:39] |
| [问：ecnanjing
_EBY7E] |
如果用AD5933这样的器件来做车辆监控,产品埋在路面下,电源如何解决? |
| [答：Mariah] |
You can use the battery as the power supply. |
[2005-8-12 10:45:41] |
| [问：dspyzd] |
贵公司的此类传感器能否提供样品和评估板开发资料？该传感器是否具有耐高温特性（如125度）？ |
| [答：Fountain] |
They"re not sensors, just sensor conditioning ICs, you can apply free
samples from our website, and you can download the Evaluation board material
from our website,both IDC and CDC can work in 125 degree circumstance |
[2005-8-12 10:45:42] |
| [问：cjf308] |
对空气湿度的测量时，它的电容值跟温度还有关系吗？ |
| [答：Mariah] |
It depends on the performance of the capacitor sensor. For most cases,
it needs temperature compensation. |
[2005-8-12 10:50:32] |
| [问：david_leemo] |
主要应用，特别是在家电方面的例子 |
| [答：Yiming] |
比如干手器就是一个电容检测在家电中的应用。 |
[2005-8-12 10:51:02] |
| [问：allenzn] |
请问，AD7745的I2C输出的信号是否表示测量的电容值？ |
| [答：Mariah] |
Yes, it is the A-D conversion result. |
[2005-8-12 10:52:00] |
| [问：kwoping] |
请问高精度电容数字转换器和阻抗数字转换器可以实现阻抗分析仪的功能吗？测量有效频率范围是多少？大概的料单成本是多少？不要求精确。 |
| [答：Fountain] |
The IDC can analyze the impedance characteristics, so it can fulfill
the function, for detailed information, please see the datasheets of AD5933,
for the price, it depends the components you want to use. |
[2005-8-12 10:52:33] |
| [问：mzhang] |
这类器件其实是把信号调理电路和数据转换器集成在一起的混合信号电路，设计中电源和地有什么需要注意之处？ |
| [答：Mariah] |
For high precision mixed signal IC, power supply and grounding layout
is very critical to get high performance of the part. Gegernally speaking,
separate analog and digital power supply and ground is needed. For details,
please refer to the datasheet. It will give the guideline of layout in
detail. |
[2005-8-12 10:57:37] |
| [问：adamzhao] |
你好，首先感谢ADI提供的样片！
请问用AD5933测量色环电阻的时候，测量的虚部不为0，但是模是对的，可能的原因有那些？ |
| [答：Yiming] |
This is due to the resistor is not an ideal one. there are some parasitical
element, such as capacitor and inductor. |
[2005-8-12 11:05:27] |
| [问：guangong] |
您好，请问贵公司的电容传感器在湿度测量方面与普通传感器相比有何优点？精度是否能够提高？ |
| [答：Fountain] |
If your temperature sensor is a capacitive type, you can use this kind
of part, but do you use this kind of sensor? If you ask the temp sensor
of this part, it"s only used to fulfill temperature compensation |
[2005-8-12 11:05:33] |
| [问：zzkeng] |
湿度传感器测量中如何解决时漂和温漂问题? |
| [答：Fountain] |
You can use our auto-zero amplifiers, like AD8628 and AD8555, which
eliminate all the low frequency noises |
[2005-8-12 11:06:26] |
| [问：cdneko] |
AD5933的评测软件除频率与阻抗曲线，还提供了哪些评测信息？其具体下载网址及使用方法是什吗？ |
| [答：Yiming] |
Please visit http://www.analog.com/Analog_Root/static/techsupport
/designtools/interactivetools/ad593x/ad593x.html. |
[2005-8-12 11:06:37] |
| [问：xujian2005] |
上述介绍的器件其功耗是否已小到能用于汽车轮胎气压检测的程度？体积呢？
谢谢！ |
| [答：Mariah] |
The Idd is 700uA for 3V power supply. In power down mode, the current
is only 0.5uA typical. The package is 16pin TSSOP. |
[2005-8-12 11:07:42] |
| [问：zzkeng] |
ADI的IDC是否支持＂一线总线＂接口?能否组网? |
| [答：Yiming] |
It is I2C bus. |
[2005-8-12 11:07:51] |
| [问：cjf308] |
AD7745中的REFIN资料中说对CDC没有用，但是我看刚才的演讲中用到了参考电压，请解释一下，谢谢 |
| [答：Fountain] |
You can use internal reference or external reference, in general, use
good external reference for high resolution ADCs can reach higher resolution |
[2005-8-12 11:09:12] |
| [问：2123063] |
在应用中，当电源波动比较大时，传感器的输出有多大的变化？ |
| [答：Mariah] |
The ripple of the power supply impacts the measure result. It depends
on the PSRR of the part. |
[2005-8-12 11:10:35] |
| [问：lbgy] |
请问在温度测量中需要考虑些什么因素？是不是一定需要环境的温度补偿？补偿的形式一般都有那些？谢谢！ |
| [答：Mariah] |
Our parts are used for capacitor and impedance measurement. The temperature
sensor inside the part is used to compensate the result for temperature
change. |
[2005-8-12 11:15:13] |
| [问：mrrf] |
请问，ad5933资料上说的impedance range是100~20M欧。是指电阻值还是包括容抗、感抗的范围?如果待测的是一个电阻和电感串联元件,那么最终，I2C输出的数据怎么表示虚阻抗(即感抗部份) |
| [答：Yiming] |
It is impedence value, not just real part.
The real part and imaginary part are located in different registers. |
[2005-8-12 11:16:37] |
| [问：cjf308] |
使用ad7745 的CDC时，REFIN(+)和REFIN(-)两个引脚需不需要连接参考电压哪？ |
| [答：Fountain] |
If you want to get higher resolution, you can try better external references,
or you can just use internal reference. In common applicaions, the internal
reference is enough |
[2005-8-12 11:18:30] |
| [问：mzhang] |
请问器件内部的可变增益放大器是数控的吗？ |
| [答：Mariah] |
For general purpose sigma-delta ADCs from ADI, the PGA is programmable
by digital method. |
[2005-8-12 11:19:30] |
| [问：mzhang] |
请问使用模拟温度传感器做温度补偿时，其输出可作为器件内sigmal-delta converter的输入吗？ |
| [答：Fountain] |
Do you mean the on chip temperature sensor of AD7745/46? If so, it just
use the same ADC core with the capacitor input. |
[2005-8-12 11:20:41] |
| [问：lbgy] |
怎样处理测试汽车发动机温度时的干扰问题？ |
| [答：Fountain] |
I"m not sure your application and your solution, but you need do temperature
compensation. |
[2005-8-12 11:22:34] |
| [问：cdneko] |
AD5933与AD5934除转换速率的区别外，性能指标还有何差距？分别适用于那种设计环境？ |
| [答：Yiming] |
AD5933 : Selectable system clock: Internal RC oscillator or external
clock
AD5934: external clock.
Please see the datasheet for application. |
[2005-8-12 11:25:15] |
| [问：cjf308] |
温度传感器是集成到芯片内部的吗？还是需要外接，再通过芯片进行AD采样哪？ |
| [答：Mariah] |
AD7745 and AD7746 have internal temperature sensor. |
[2005-8-12 11:29:20] |
| [问：cdneko] |
介绍AD5933时提到用户需选择外接反馈电阻，那如何选择外接反馈电阻，来保证系统的线性特性，参考依据是什吗？ |
| [答：Yiming] |
The user should choose a feedback resistance value which, in conjunction
with the selected gain of the PGA stage, maintains the signal within the
linear range of the ADC (0 V to VDD). |
[2005-8-12 11:30:48] |
| [问：zzkeng] |
ADI的IDC或CDC最多能同时连接多少个传感器? |
| [答：Fountain] |
For CDC, AD7746 can measure 4 capacitor type sensors, you can also conncet
a temperature sensor or other kind of input to its differential voltage
input, for detailed info, please see the datasheet, thanks. |
[2005-8-12 11:31:56] |
| [问：maeleton1] |
ADI的阻抗转换器能否直接连接传感器?是否有小信号调理电路? |
| [答：Yiming] |
Yes, it can direct connect the impedance. There is amplifer
in the receiver side. |
[2005-8-12 11:33:04] |
| [问：xujian2005] |
能否提供用于湿度传感，精度不需要高（家电应用），价格比较低的器件型号？谢谢！ |
| [答：Yiming] |
AD7745 |
[2005-8-12 11:35:54] |
| [问：wangjunhu] |
请问ADI有没有用于触摸屏设计的芯片和方案？谢谢！ |
| [答：Mariah] |
AD7843/7873/7877 for resistance touch panel digitizer. AD7142 for capacitance
touch panel design. |
[2005-8-12 11:37:16] |
| [问：332599] |
请问AD5933资料在那可以找到? |
| [答：Mariah] |
You can find it in our website. www.analog.com |
[2005-8-12 11:37:41] |
| [问：encaon] |
ADI的阻抗转换器是否具有对传感器进行供电的功能?是采用三线制供电方式吗? |
| [答：Yiming] |
I don"t know what you mean. Only two line connect to the impedance sensor. |
[2005-8-12 11:39:26] |
| [问：meteor_chu] |
双电极电容传感器的双电极是否要完全一致?如果不一致,会带来那种误差?如何消除? |
| [答：Fountain] |
Do you mean the differential input type, if so, the part just measure
their difference |
[2005-8-12 11:39:57] |
| [问：yinyan] |
电容传感器在接近位置的检测中，如何保证检测距离的精确性？？ |
| [答：Fountain] |
1. to select the high precision sensor,
2. use this kind of high resolution converter like AD7745/46
3. use temperature compensation
4. careful layout |
[2005-8-12 11:41:33] |
| [问：wuhb] |
使用芯片ad5933时，对pcb布板有什么要求？ |
| [答：Mariah] |
The best way is to refer to the layout of our evaluation board. The
evaluation board information can be found in the website. |
[2005-8-12 11:42:32] |
| [问：kllyj2008] |
多路测量温度中如何提高扫描速度? |
| [答：Mariah] |
Today"s focus is capacitance and impedance measurement. For temperature
sensing, please call our technical support hotline 800-810-1742. |
[2005-8-12 11:43:43] |
| [问：cjf308] |
高温会增大被测物质的电容还是减小被测物质的电容，还是在不同的点不一样哪？ |
| [答：Fountain] |
It depends the cap sensor type, please check its datasheet for guide |
[2005-8-12 11:44:25] |
| [问：da2100] |
in fuel cell /battery impedance measurement
application, it usually requires measuring low frequency impedance with
high transfer rate. what"s the delay and set time for the AD5933 |
| [答：Yiming] |
The SETTLING TIME CYCLES register value determines the delay between
a Frequency Start/Increment/Repeat command and the time an ADC conversion
commences. |
[2005-8-12 11:44:49] |
| [问：eric_r] |
对于此类电容式或阻抗式数字转换器，如何消除测量中的非线性误差？ |
| [答：Mariah] |
You can implement calibration or curve fit in software to remove the
nonlinear error. |
[2005-8-12 11:47:31] |
| [问：mrrf] |
我想知道adi有没有能用在射频上的阻抗测量芯片。因为是50欧的系统，阻抗都很小.有吗？ |
| [答：Mariah] |
We do not integrated solution. But you can use our DDS products to do
that, for example AD9858. |
[2005-8-12 11:49:15] |
| [问：zypbj2000] |
从AD5933的原理框图中只见到一个ADC（测量被测阻抗），实部的测量是如何实现的？DSP输出的数据是计算好的阻抗值和相位值？还是只是实部值和虚部值？ |
| [答：Yiming] |
The outputs are real and imaginary parts. |
[2005-8-12 11:49:17] |
| [问：redhilltea] |
AD7745的电容测量精度有多少？如何确定？ |
| [答：Fountain] |
It can reach 18.5 bit Vpp resolution, it have relationship with the
speed, please see table of 5 of AD7745"s datasheet |
[2005-8-12 11:51:36] |
| [问：lvbin1980] |
请问ad7745的线性误差和转换速度是多少？ |
| [答：Fountain] |
for higher resolution, it will be lower speed, the detailed information
can be found in AD7745"s datasheet. |
[2005-8-12 11:53:16] |
| [问：guangong] |
请问AD7745用于湿度测量时是否还需要外接温度补偿电路？谢谢！ |
| [答：Fountain] |
It depends your application and system requirements, it has a on chip
temperature sensor to do the temp compensation, you can also connect a
RTD sensor to its differential voltage input |
[2005-8-12 11:54:41] |
| [问：adamzhao] |
在材料的阻抗测量中，要想达到较高的精度，除了电源和地需要考虑外，有没有其它要考虑的方面？ |
| [答：Yiming] |
The system clock speed should be considered in different impedance values.
For example:In order to achieve system accuracy from the 0.1 kHz to 1
kHz region, the system clock needs to be scaled down from the 16.776 MHz
nominal clock frequency to 500 kHz, typically. Also, reference is very
important:initial accuracy, ppm drift, long-term drift, and output voltage
noise. |
[2005-8-12 11:55:22] |
| [主持人：ChinaECNet] |
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或 lilin@chinaecnet.com)。 |
[2005-8-12 11:57:38] |
| [问：cjf308] |
ad7745中，是不是设置DAC的作用除了具有增大测量电容值外，还有去耦合的作用？同Cpa 和Cpb |
| [答：Fountain] |
the DACs are only used to enlarge the measurement range, they act as
negative capacitaces |
[2005-8-12 11:59:49] |
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