如何确定峰值信号的上升/下降时间？

yigitt写道：
大家好，
我开发了一个用于Spartan 3e套件的VHDL PWM生成算法，一切都是预期的。
但我想了解这个信号的上升/下降时间，模拟显示理想的行为，但在范围上我看到的东西不同。
从理论上讲，如何确定峰值信号的上升/下降时间？
我把C9作为时钟源并进行倍频。
我希望有经验的用户提供一些指导。
干杯。
您需要快速的“范围探测以及快速”范围。
您需要一个非常短的路径，从接地点非常靠近要测量的信号和探头的地面。
所有Tek和安捷伦的示波器探头都配有一个套件，其中包括一个小弯头弹簧，它可以绕探头尖端滑动，并有一个接地的点。
在约翰逊和格雷厄姆的“高速数字设计”一书中，对这个话题进行了很好的讨论。
买这本书。
阅读。
----------------------------是的，我这样做是为了谋生。



以下为原文

yigitt wrote:
Hi all,
 
I developed a PWM generation algorithm in VHDL for Spartan 3e kit and everything is expected. But I would like to learn about the rise/fall times of this signal, simulation shows the ideal behavior but on the scope I see things different. From the theoretical approach how can I determine the rise/fall times of a peak signal ?
 
I take C9 as the clock source and do frequency multiplication.
 
I would appreciate some guidance from experienced users.
 
Cheers.

You need a fast 'scope probe along with a fast 'scope.
 
You need a VERY short path from a ground point that is very near the signal to measure and the probe's ground. All Tek and Agilent 'scope probes come with a kit which includes a little curlicue spring guy which slips around the probe tip and has a point that goes to the ground.
 
There is a great discussion of this very topic in Johnson and Graham's "High Speed Digital Design" book.  Buy the book. Read it.
----------------------------Yes, I do this for a living.

从产品的数据表中我找不到有关信号的最小/理想上升/下降时间的任何信息。
由于它来自切换到开/关的时间，因此应该有最小值？



以下为原文

From the datasheet of the product I couldnt find any info regarding the minimum/ideal rise/fall times of a signal. Since it originates from the time for the switch to on/off, there should be a minimum value for this ?

Y，
信号完整性取决于负载，pcb，配置等。
它由Xilinx提供的IBIS模型指定。
使用它们。
Austin Lesea主要工程师Xilinx San Jose



以下为原文

y,
 
Signal Integrity depends on load, pcb, configuration, etc.
 
It is specified by the IBIS models Xilinx delivers.
 
Use them.
 
 
Austin Lesea
Principal Engineer
Xilinx San Jose

你能解释为什么你对PWM输出的上升和下降时间感兴趣吗？
- 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？
你能找到手册吗？2。
搜索论坛（并搜索网页）以寻找类似的主题。
不要在多个论坛上发布相同的问题。
不要在别人的主题上发布新主题或问题，开始新的主题！5。
学生：复制代码与学习设计不同.6“它不起作用”不是一个可以回答的问题。
提供有用的详细信息（请与网页，数据表链接）.7。
您的代码中的评论不需要支付额外费用。
我没有支付论坛帖子的费用。
如果我写一篇好文章，那么我一无所获。



以下为原文

Can you explain why you are interested in the rise and fall times of your PWM output?
 
-- Bob Elkind
SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

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