Spartan 3E入门套件板载ADC的偏差输出

嗨，
有关ADC的具体信息，请参阅LTC 1407A数据表。
在那里，您还可以阅读有关数值范围和界面详细信息的信息。
ADC的奇怪结果可能有很多原因。
这可能是一些时序问题，导致在错误的时间读取某些位。
或者你只是误解了两个补码值。
或者您的模拟设置可能有问题。
您是否能够测量ADC输入端的真实输入电压？
还要记住，参考电压为1.65V，因此与参考电压相比，您的1V信号被视为“负”电压。参考电压仅来自3.3V电源电压的两个电阻。
小的VCC偏差或噪声可能会对GAIN和ADC结果产生影响（参见电路板用户指南的图10-2）。
有一个很好的综合 
Eilert



以下为原文

Hi,
for specific informations about the ADC you should consult the LTC 1407A datasheet.
There you can also read about the numeric range and the interface details.
 
The strange results from the ADC can have many causes.
It may be some timing issue, that causes some bits to be read at the wrong time. Or you just misinterpreted the two's complement value.
Or there may be something wrong with your analog setup. Were you able to measure the true input voltage at the ADCs input?
Also keep in mind, that the reference voltage is 1.65V, so your 1V signal is seen as a "negative" voltage compared to the reference.And the reference is just derived by two resistors from the 3.3V supply voltage. Small VCC deviations or noise may have impact to the GAIN and ADC results (see Figure 10-2 of the boards User Guide).
 
Have a nice synthesis
  Eilert

谢谢你的建议。
能否请您解释一下我如何直接在ADC输入端输入真正的输入电压？



以下为原文

Thanx for the suggestions.
Could you please explain me how can I true input voltage at ADC's input directly?

能否请您解释一下我如何直接在ADC输入端输入真正的输入电压？
附近是否有知识渊博且经验丰富的设计工程师可以帮助向您解释入门套件电路板原理图以及LTC1407和LTC6912数据表？
也许你的导师可以帮助你？
- 鲍勃埃尔金德
签名：新手的自述文件在这里：http：//forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369总结：1。
阅读手册或用户指南。
你读过手册了吗？
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以下为原文

Could you please explain me how can I true input voltage at ADC's input directly?
 
Is there a knowledgeable and experienced design engineer nearby who can help explain to you the Starter Kit board schematics and the LTC1407 and LTC6912 datasheets?  Perhaps your instructor might be able to help you?
 
-- Bob Elkind
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嗨，
您可以使用电压表来获得直流信号的平均值。
或者您可以使用示波器，这样您也可以看到该信号的噪声容限。
无论如何，请小心使用探头，这样就不会缩短任何引脚并导致电路板损坏。
如果可能的话，请按照Bob的建议：向一些有经验的工程师寻求帮助。
有一个很好的综合 
Eilert



以下为原文

Hi,
you can use a voltmeter for an averaged value of your DC signal.
Or you can use an Oscilloscope, so you can also see the noise margin of that signal.
 
In any way, be VERY careful with the probes, so you don't shorten any pins and cause damage to the board.
If possible do as Bob sugggested: Ask some experienced engineer for help.
 
Have a nice synthesis
  Eilert