如何计算输出时钟的DISCRETE JITTER？

实际上我在玩14.2后的答案是：
par总是从I0和BUFGMUX的I1输出更差的JITTER（PRIORITY没有任何作用）
现在我同意了
谢谢，
在原帖中查看解决方案



以下为原文

Actually my answer after playing with 14.2 is:
par always take worse JITTER from I0 and I1 of BUFGMUX for output (no role for PRIORITY)
And now I agree with it
 
Thank you,
View solution in original post

嗨，请参阅下面的AR：http：//www.xilinx.com/support/answers/13645.htmlhttp：//www.xilinx.com/support/answers/39898.htmThanks,Yash



以下为原文

Hi,

Refer below AR:
http://www.xilinx.com/support/answers/13645.html
http://www.xilinx.com/support/answers/39898.htm

Thanks,
Yash

yashp，
我觉得你没有感觉到这个问题。
这个答案记录没有说BUFGCTRL，它有两个时钟作为输入。



以下为原文

yashp,
 
I think you didnt feel the quiestion.
 
This answer records say nothing about BUFGCTRL which gets two clocks as inputs.

嗨，
根据您要分析时间的时钟，给出优先级关键字。
使用下面的PRIORITY关键字检查示例PERIOD约束。
在更快的时钟上使用PRIORITY。
但是通常我在BUFGMUX上使用了PRIORITY。
没有在BUFGCTRL上测试它。
NET“clk1”TNM_NET = clk1;
TIMESPEC TS_clk_1 = PERIOD“clk1”8 ns HIGH 50％PRIORITY 1;
NET“clk2”TNM_NET = clk2;
TIMESPEC TS_clk_2 = PERIOD“clk2”10 ns HIGH 50％PRIORITY 2;
如果您没有给出任何优先级，理想情况下，该工具会进行最差情况分析，并根据最坏情况参数计算时序。
如果分析是在最坏情况CLOCK，即具有最小周期的时钟，那么你不必担心慢速时钟。
希望这说清楚。
谢谢，AnirudhPS：请将此标记作为答案，以防它有助于解决您的问题。如果帖子引导您找到解决方案，请给予赞誉。



以下为原文

Hi,
 
Give the priority keyword, based on, which clock you want to analyze the timing for. Check the example PERIOD constraint with the PRIORITY keyword below. Use PRIORITY on the faster clock. 
 
However generally i have used PRIORITY on BUFGMUX where it works. Havent't tested it on BUFGCTRL.
 
NET "clk1" TNM_NET = clk1;
TIMESPEC TS_clk_1 = PERIOD "clk1" 8 ns HIGH 50% PRIORITY 1;NET "clk2" TNM_NET = clk2;TIMESPEC TS_clk_2 = PERIOD "clk2" 10 ns HIGH 50% PRIORITY 2; If you do not give any PRIORITY, ideally, the tool does a worst case analysis and calculates the timing based on the worst case parameters. If the analysis is made on the worst case CLOCK, i.e the clock with minimum period, then you need not worry about the slow clock.  Hope this makes it clear.Thanks,
Anirudh

PS: Please MARK this as an answer in case it helped resolve your query.Give kudos in case the post guided you to a solution.

Yash＆amp;
Anirudh已经在最大程度上回答了你的问题。当你有两个时钟驱动BUFGCTRL时，那么根据时序约束中时钟上定义的优先级，两个时钟中的一个将被考虑用于计算抖动或时序
但是，当没有定义周期约束时，工具将在pcf中选择最新约束，即如果在clk2的周期约束之前定义clk1的周期约束，则将考虑clk2进行时序分析。
--------------------------------------------------
---------------------------------------------请将帖子标记为
如果提供的信息能够回答您的问题/解决您的问题，请“接受为解决方案”。给予您认为有用的帖子。



以下为原文

Yash & Anirudh have answered your question to most extent.

When you have two clocks driving a BUFGCTRL, then based on the priority level defined on the clocks in the timing constraints, one of the two clocks will be taken into account for calculating the jitter or for timing analysis.

But when no period constraint is defined, the tool will pick the latest constraint in pcf i.e. if the period constraint of clk1 is defined before the period constraint of clk2 then clk2 will be considered for timing analysis.-----------------------------------------------------------------------------------------------
Please mark the post as "Accept as solution" if the information provided answers your query/resolves your issue.

Give Kudos to a post which you think is helpful.

问题是 -  BUFGCTRL之后的JITTER。
我试过PRIORITY但总是得到 
时钟不确定度：0.244ns时钟不确定度：0.244ns（（TSJ ^ 2 + DJ ^ 2）^ 1/2）/ 2 + PE总系统抖动（TSJ）：0.000ns离散抖动（DJ）：0.335ns相位误差（PE
）：0.076ns
在BUFGMUX之后
和 
时钟不确定度：0.117ns时钟不确定度：0.117ns（（TSJ ^ 2 + DJ ^ 2）^ 1/2）/ 2 + PE总系统抖动（TSJ）：0.000ns离散抖动（DJ）：0.079ns相位误差（PE
）：0.076ns
没有BUFGMUX。
并且不能对此做任何事情。



以下为原文

The question was - JITTER after BUFGCTRL.
I tried PRIORITY but always get
 
  Clock Uncertainty:    0.244ns

  Clock Uncertainty:          0.244ns  ((TSJ^2 + DJ^2)^1/2) / 2 + PE
    Total System Jitter (TSJ):  0.000ns
    Discrete Jitter (DJ):       0.335ns
    Phase Error (PE):           0.076ns
 
after BUFGMUX
 
and
 
  Clock Uncertainty:    0.117ns

  Clock Uncertainty:          0.117ns  ((TSJ^2 + DJ^2)^1/2) / 2 + PE
    Total System Jitter (TSJ):  0.000ns
    Discrete Jitter (DJ):       0.079ns
    Phase Error (PE):           0.076ns
 
without BUFGMUX.
 
and cant do anything with this.

实际上我在玩14.2后的答案是：
par总是从I0和BUFGMUX的I1输出更差的JITTER（PRIORITY没有任何作用）
现在我同意了
谢谢，



以下为原文

Actually my answer after playing with 14.2 is:
par always take worse JITTER from I0 and I1 of BUFGMUX for output (no role for PRIORITY)
And now I agree with it
 
Thank you,