|
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m********e
发帖数: 585 | 3 (1) sawtooth is integration of square wave. if use schmitt-trigger to
generate sawtooth, use any integrator design.
(2) or use a counter + DAC. |
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m********e
发帖数: 585 | 5 I mean you can use digital + DAC. Use a counter to increase the #, then
reduce the #, and output by DAC. |
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a*****s
发帖数: 6260 | 6 他要你找个并口输入的DAC，再弄个计数器加一点逻辑，正向走完了走反向，如此
反复。 |
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ET
发帖数: 10701 | 7 调查了一下，大概明白了。
似乎这种方法是现在用的比较多的一种。 |
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a****l
发帖数: 8211 | 8 I believe this is a tradeoff between simplicity and flexibility. |
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ET
发帖数: 10701 | 9 老大来看这个图帮我解释解释吧。
这是教科书里的，我也见过许多application notes用这个。
2个control loops都在那了（好，我不懂control, 我懂一点feedback).
右边的图是个peak current control的示意图。is(t) 到达ic(t)的时候， q1 off.
这个coomparator能做到。 你能解释下，ic(t)是怎么define的吗？我不是问它怎么来
的。我看得到出是从compensator里出来的，但ic(t)是如何就能在稳定态的时候，是is
(t)的peak 值。。这里的数学公式有吗？
ic(t) = (v(t)-vref)*Gm (Gm is the error amp.'s transconductance).
另外，能解释下，如果是这个current mode control, 原本用于voltage mode的
sawtooth waveform就不需要了？ |
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l****r
发帖数: 97 | 10 Final settled value is c1/(c1+c2).
The question asks for waveform at B.
Assume voltage is 0 at B at the begining. Key is to realize the switch
resistance is not 0 and voltage at across a cap is continuous. |
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r*******r
发帖数: 1014 | 11 (1)cadence spectreRF 在 phase noise 上还是有些人品的.
5.0前没有的原因可能是bell lab的 phase noise 的牛paper前8年才出来。
(2)1/f is still difficult to verify at transient level if you care your time
-domain waveform distortion. if quant-error is small then it's an issue for
adc.
(3)how ot optmize for design it is still unknown; how to model it beyond 40nm is also unknown recently.
con
了。 |
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d****o
发帖数: 1112 | 12 faint....I2C is open drain...you should only have one pull-up for SDA or SCL
across whole bus...
I guess the problem is your EEPROM is 5V part as you said, which may have VI
H as high as 3.3V or above but your pull-up can't drive that high.
Hook up a scope to take some screenshots of I2C waveforms, and read your dat
asheet carefully... |
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T******T
发帖数: 3066 | 13 Have seen many I2C issues over the years, like everyone is saying matching
voltage rail is important, and tweaking the pullup resistors with respect to
your bus capacitive load will also help.
1) Check you SDA/SCL waveform, do you have timing violation induced by
excessive loading (spiky looking edges) ? If so, reduce SCL speed, increase
pull-up strength (not too much as that'll raise your effective VOL).
2) Check your SDA/SCL output swing from the processor, and the response
traffic output swi |
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o****m
发帖数: 633 | 14 digital_integrated_circuits_a_design_perspective__2nd_ed
P235
There is a graph demonstrating the waveform for NAND cmos gate. |
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s**g
发帖数: 66 | 15 Q3: remove rx side cap
you listed one reason: line + cap would have filter effect
I like to push the envelope:
driver normally handles its immediate load better, e.g. linear driver with
voltage mode feedback. Load cap at TX side won't affect output waveform by
much. However, receiver side cap causes delay/ISI/filtering, which can't be
corrected by TX side feedback and thus shall be avoided.
Similar effect can be found in CML/ECL logics. |
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w******r
发帖数: 25 | 16 Is there any simulation package that will give measured voltages, currents,
powers in a smart grid system with some generators and loads?
I am looking for something that can generate the waveforms for a linear
state space model which I use to describe the smart grid system.
Thank you very much! |
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w******r
发帖数: 25 | 17 I want to be able to simulate the system with several generators, loads
described in the reference paper.
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4539776
I am attaching the reference paper (the link above).I want to be able to
simulate (very accurately) the kinds of systems they describe.These are
dynamical systems with spinning generators that change speed and thus the
waveforms change frequency....
Thank you very much! |
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w******r
发帖数: 25 | 18 I want to be able to simulate the system with several generators, loads
described in the reference paper.
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4539776
I am attaching the reference paper (the link above).I want to be able to
simulate (very accurately) the kinds of systems they describe.These are
dynamical systems with spinning generators that change speed and thus the
waveforms change frequency....
Thank you very much!
and |
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g******u
发帖数: 3060 | 19 this kind of question is stupid.
say for ideal capacitor, the overshoot is infinity. ok nothing is ideal,
then how can you draw 'non-ideal' waveform from there? |
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g****t
发帖数: 31659 | 20 你没做过两个相同的电容并联中间接一个开关,
初始状态一个有电荷Q.然后开关一合,问到稳态后能量消失到哪儿那个题吧?
我觉得，这个题和那个是类似的。
this kind of question is stupid.
say for ideal capacitor, the overshoot is infinity. ok nothing is ideal,
then how can you draw 'non-ideal' waveform from there? |
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p***e
发帖数: 472 | 21 The voltage measure sensitivity of most digital oscilloscopes is in the
order of mV/div. Some keithley digital multimeter allows a PC to read /
store the measurement with certain sampling rate. Then you can plot it to
see the waveform. You may be able to rent such equipment if you only need
it temporarily. Just google it.
，还要考虑直流offset，放大器输入阻抗，等等。如果没经验，这活你干不了。我猜你
可能想看波形，高精度万用表只能测直流，看不了波形的。 |
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p***e
发帖数: 472 | 22 compare waveforms on oscilloscope. |
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F*********n
发帖数: 52 | 23 呵呵，问题解决了。基本上就是基带I和Q的waveform一样，然后输出有90度相移就是
single sideband modulation了。也就是BPSK可以做single sideband,但QPSK,QAM肯定
不是了。还是安捷伦的App Note和公司的老鸟比较容易得到答案啊！ |
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K**********n
发帖数: 1197 | 24 学术界珍稀有限的原版外文资料，
Remote Mind Control Technology
Reprinted from SECRET AND SUPPRESSED: BANNED IDEAS AND HIDDEN
HISTORY, edited by Jim Keith, $12.95, available from
1-800-680-INET.
There had been an ongoing controversy over health effects of electromagnetic
fields (EMF) for years (e.g., extremely low frequency radiation and the
Navy's Project Seafarer; emissions of high power lines and video display
terminals; radar and other military and industrial sources of radio
frequencies and micr... 阅读全帖 |
|
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z*****n
发帖数: 7639 | 26 没看出来能生成1GHz方波。
只看到这句：
A real-world digital square wave rarely resembles its theoretical counterpar
t. Since the AWG70000A Series is an analog waveform source, it is the perfec
t single-box solution that is used to create digital data streams and mimic
the analog imperfections that occur in real-world environments.
THD和jitter指标都没有。 |
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r*c
发帖数: 16750 | 27 谢谢。我联系vendor了，看来sales的信息有点错误。如果用我找到的那些RF waveform
generator成本太高，我也没法集成到我的系统中。
但现在基本找到方案了。 |
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m**a
发帖数: 1840 | 28 朋友大作，发在知乎。欢迎点赞和转发。
https://www.zhihu.com/question/52732376
美国当地时间11月17日凌晨0点45分，在刚刚结束的3GPP RAN1 87次会议的5G信道编码
方案讨论中，经过艰苦卓绝的努力和万分残酷的竞争，以中国华为公司主推的Polar
Code（极化码）方案，成为5G控制信道eMBB场景编码方案。
编者按
“华为极化码事件”内幕：
极化码获得的并非之前大肆炒作的“短码”。
极化码打败的对手并不是LDPC，而是在控制信道上取代4G现有技术TBCC。
若非极化码最终靠非技术手腕挤进控制信道，华为投资几十亿的5G“三神器”在5G NR
第一阶段业已全部打水漂。
整个5G信道编码又经历一番怎样波澜壮阔的争斗，这背后又隐藏着多少暗流汹涌的阴谋
诡计。“为极解密” 为您最全方位的解析。
为极解密
作者：见南山
第一章 极之澄清
第一章 第一节 5G到底哪一部分码会考虑使用极化码？
第一章 第二节 极化码在长码上真的是几票惜败于LDPC么？
第一章 第三节 5G NR 极化码到底打败了谁？
第二章 极化之源
第二章 第一节 前5G -- 毫... 阅读全帖 |
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t******e
发帖数: 114 | 29 如果oscillation waveform 被AM modulated，会同时产生FM modulation吗？会影响
frequency stability 吧？ 有关这方面的文章麻烦推荐一下,谢谢。 |
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t*****a
发帖数: 40 | 30 是一款模拟地震勘探图的软件。
叫Waveform Inversion, by Gerhard Pratt (1999).
但是我找不到这款软件的说明。
请问哪里有说明？
谁用过？
另外，谁能推荐相关的好软件么。
我的目标是假定地层下的速度分布状况已知，用一款软件模拟
地震勘探所得到的图。
哪位大侠能推荐一下么？
谢谢！ |
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jl
发帖数: 398 | 31 跟 harr 小波还是不一样的. 我用的 square wave = sign ( sin or cos ).
不知道有没有什么定理 说 跟 sin, cos对应的 waveform 是Complete Orthogonal System? |
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w******z
发帖数: 1872 | 32 cardiac surgical ICU. PA cath flow can be done at the bedside in the ICU
occasionally. Usually the residents do it. As bedside nurses, we assist the
procedure. CRNA might do it in some hospitals. It is not a nursing procedure
. You could look for observation opportunities in the CVICU. It is more
difficult to get into OR for OB, but you will get better opportunities in
the CVICU. Honestly, watch couple youtube videos, you will get it all. It is
all about when to inflate the balloon according to ... 阅读全帖 |
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T*******y
发帖数: 6523 | 33 Thanks to acidia and truthmostcom for your responses. I do not major in
physics, could you explain a bit more?
Is that claim that the waveform function is real, but not a statistical
distribution, true? |
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B***y
发帖数: 83 | 34
1) Is Wij some function of t or just some constant depending on (i-j) ?
2) what is the exact meaning of " the moving profile is keeping its waveform"
and " a cost function for this"?
It will be helpful if you can make it clear. |
|
R*******t
发帖数: 367 | 35 Carotid stenosis and renal artery stenosis at 60-70% is not critical. I have
seen a lot of patients follow even more severe stenosis.
Your father eventually needs diagnostic angiogram with aortic and bilateral
lower extremities run-off to evaluate for occlusion. Or he should at least
get arterial dopplers to check the waveforms and ABI (ankle brachial index)
first. |
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f**d
发帖数: 768 | 36 这是一本计算神经科学的优秀著作，全文拷贝这里（图和公式缺），有兴趣的同学可以
阅读
如需要，我可以分享PDF文件（－－仅供个人学习，无商业用途）
From Computer to Brain
William W. Lytton
From Computer to Brain
Foundations of Computational Neuroscience
Springer
William W. Lytton, M.D.
Associate Professor, State University of New York, Downstato, Brooklyn, NY
Visiting Associate Professor, University of Wisconsin, Madison
Visiting Associate Professor, Polytechnic University, Brooklyn, NY
Staff Neurologist., Kings County Hospital, Brooklyn, NY
In From Computer to Brain: ... 阅读全帖 |
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w*******y
发帖数: 60932 | 37 Vaans:
http://www.vanns.com/shop/servlet/item/features/753029720/apc-j10
has the Silver APC J10 Home Theater UPS on sale for $150 with free
shipping. This model is 1000VA/600W. Really good deal for an APC UPS,
normally sells for $350-$500. You can use this to protect your AV gear or
get one for your computer.
Comparison Specifications
* Output Power Capacity: 600W / 1000VA
* Max Configurable Power: 600W / 100VA
* Waveform Type: Stepped Approximation To A Sinewave
* Output Co |
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