f*********t
发帖数: 37 | 1 Well, I was talking about perfect sampling. I guess the original question
was about perfect sampling. This is just my guess because this is an
assumption in many DSP books when no specific sampling methods are specified
.
After sampling, continuous signals are sampled to discrete signal. Discrete
signal has periodic power spectrum. Based on this, we usually only consider
the power spectrum of baseband discrete signal winthin one period which is [
-fs/2 fs/2]. So not only for noise but also for a |
|
f*********t
发帖数: 37 | 2 hehe please give me a matlab code of FFT of any signal (I mean ANY) at
sampling rate, say, 1MHz. Let me see how do you get the spectrum components
out of 1MHz.
BTW, don't ask question such as 'do you really understand what is XXX?'.
This won't make you more convincing and will make
communication harder.
do
signal is discrete in aptitude, but still continuous in time.
. |
|
f*********t
发帖数: 37 | 3 yeah its like
y(t) ---> y(n*Ts)+Q(n*Ts) and Q(n*Ts) is the quatization noise.
|
|
T******n
发帖数: 3180 | 4 你们一个在讲AD
另一个在讲DA
差不多就是这样 |
|
c**l
发帖数: 159 | 5 It depends on quantization noise level in DSM output and whether you
decimate to 2 Fs or 4 Fs. You have to run sim to verify your final numbers.
Check the original Hogenauer paper to get a better view of the filter. |
|
c**l
发帖数: 159 | 6 Given the quantization noise level, bandwidth, and final oversampling ratio,
you should have a rough idea of the order of CIC. Once you know the order,
you can try the multi-stage trick to reduce the DC gain of the filter. In
this step, you probably have several cases to simulate to know the exact SNR
coming out.
be |
|
c*******c
发帖数: 726 | 7 ADC/DAC, COMPARATOR, PLL, RF FILTER(partially), QUANTIZER
Anything in communication system prior to and after DSP circuits is in such
realm.
Hope it makes sense. |
|
b**********g
发帖数: 32 | 8
I am not an ADC person. For (2), generally, if one can
characterize statistical properties of quantization error,
which in your case may be dependent on the properties of u(z),
then it is possible to minimize the residual variance.
Alternatively, you can build a recursive filter to accomplish
your goal, although most RLS filters minimize error squared,
not absolute error - but you really want error squared, yes? |
|
g****t
发帖数: 31659 | 9 谢谢回复.
例如y(t)=a*y(t-1)+b*y(t-2)+c*u(t)+d*u(t-1)
这样一个滤波器.
如果只知道u有界,字长8位,那种实现,能让
|理想的y-滤波器实际产生的y|的
min max或平方积分最小,这个问题我看了下文献,好像是没有答案的.
统计特性的结果有不少.但那个我觉得帮助不大.一来统计特性很难准确.一些
文章上的结论,对不准的统计特性是不是仍然有效,这个目前为止.二来,
data sheet上,我总不能说这个东西99%不会numerical blow up吧.
I am not an ADC person. For (2), generally, if one can
characterize statistical properties of quantization error,
which in your case may be dependent on the properties of u(z),
then it is possible to minimize the residual variance.
Alt... 阅读全帖 |
|
g****t
发帖数: 31659 | 10 谢谢回复.
例如如下滤波器,字长只允许8位.
y(t)=a*y(t-1)+b*y(t-2)+c*u(t)+d*u(t-1)
保证稳定性的办法是显然的,最简单的,只要让a=b=c=d都等于零即可.
或者求解方程x^2=ax+b,然后并联实现,如果特征根小于1,
那就是两个moving average的组合.即使有量化误差,稳定性应该也没问题.
所以稳定性似乎没多大实际意义.
如果只知道|u(t)|的上界.有没有一种实现方法,使
|实现的y(t)-理论的y(t)| 的min max或者平方积分最小
另外,如果只知道上界没办法做.那么假定u(t)的频率有界,最优的实现能做吗?
overall
quantization
results |
|
|
g*****d
发帖数: 210 | 12 请问大家
一般digital filter里怎么决定wordlength跟SNR??
比如说一个half band decimation filter, fin=fs/8
有5个17-bit multiplier, 16-bit input data
这样snr怎么算
thanks a lot & happy new year |
|
w*******8
发帖数: 139 | 13 假设digital filter不会改变通带内的噪声与信号，那么带外的噪声衰减程度决定了你
可以用多少bits来表示最后的结果。一般输出的量化噪声不要大于原来的noise floor
和你希望的带外噪声水平.
不知对不对 |
|
c*******s
发帖数: 735 | 14 不加dithering会怎么样? 是in band的phase noise变差了，还是在某个freq上面?
能影响Quantization noise的原因也就那么几个，bandwidth太高，Sigma Delta Modul
ator order太低，charge pump mismatch etc. 自己做个Matlab先分析一下。 |
|
z*****n
发帖数: 7639 | 15 分清quantization noise和aliasing。 |
|
p***e
发帖数: 118 | 16 请问DSM的部分
QUANTIZER OUTPUT BIT多跟少的trade off是??
另外有什么资料可以找到比较详细的single loop dsm 是如何implement??
thanks |
|
f*******e
发帖数: 4531 | 17 Please apply online directly.
Job Id E1945678
Job Title Audio Systems Engineer (QCT Audio - San Diego, CA)
Job Overview
Qualcomm multimedia audio systems group develops a broad spectrum of
advanced audio signal processing technologies, including echo cancellation,
noise reduction, array signal processing, acoustic enhancement, voice
enhancement, active noise cancellation, audio effects, voice activation, etc
. Such technologies are broadly adopted in mobile phones, IoT (internet of
thing... 阅读全帖 |
|
t**********m
发帖数: 205 | 18 来自主题: Mathematics版 - 伟哥之乐 The joy of viXra
https://telescoper.wordpress.com/2011/05/19/
Posted in The Universe and Stuff with tags arXiv, astronomy, Cosmology,
Physics, scientific publishing, viXra on May 19, 2011 by telescoper
From time to time on this blog I post rants about the state of scientific
publishing, open access, the importance of the arXiv for astronomy and
cosmology, and so on.
This morning, however, I discovered an “alternative” side to the whole
business of online science, a site by the name of viXra. Mos... 阅读全帖 |
|
s********i
发帖数: 21 | 19 Compressed Sensing;
Sigma-delta algorithm (quantization);
Frame theory;
random matrix
google and the find them |
|
g****t
发帖数: 31659 | 20 【 以下文字转载自 Detective 讨论区 】
发信人: guvest (我爱你老婆Anna), 信区: Detective
标 题: 哪位能帮我下载一个论文吗?
发信站: BBS 未名空间站 (Wed Sep 7 21:45:22 2011, 美东)
Approximating a bandlimited function using very coarsely quantized data: A
family of stable sigma-delta modulators of arbitrary order, Annals of Math.,
158 (2)
annals.math.princeton.edu/wp-content/uploads/annals-v158-n2-p09.pdf
请发到z********[email protected],谢谢. |
|
a*********3
发帖数: 660 | 21 弗里曼•戴森 （Freeman Dyson）1923年12月15日出生，美籍英裔数学物理学家
，普林斯顿高等研究院自然科学学院荣誉退休教授。
戴森早年在剑桥大学追随著名的数学家G.H.哈代研究数学，二战结束后来到美国康奈尔
大学，跟随汉斯•贝特教授。他证明了施温格和朝永振一郎发展的变分法方法和
费曼的路径积分法的等价性，为量子电动力学的建立做出了决定性的贡献。1951年他任
康奈尔大学教授，1953年后一直任普林斯顿高等研究院教授。
《鸟和青蛙》(Birds and Frogs)是戴森应邀为美国数学会爱因斯坦讲座所起草的一篇
演讲稿，该演讲计划于2008年10月举行，但因故被取消。这篇文章全文发表于2009年2
月出版的《美国数学会志》（NOTICES OF THE AMS, VOLUME56, Number 2）。
有些数学家是鸟，其他的则是青蛙。鸟翱翔在高高的天空，俯瞰延伸至遥远地平线的广
袤的数学远景。他们喜欢那些统一我们思想、并将不同领域的诸多问题整合起来的概念
。青蛙生活在天空下的泥地里，只看到周围生长的花儿。他们乐于探索特定问题的细节
，一次只解决一... 阅读全帖 |
|
L*m
发帖数: 235 | 22 近十年ACTA上华人作者统计
ACTA
2014
Gromov–Hausdorff limits of Kähler manifolds and algebraic geometry
Simon Donaldson, Song Sun（孙崧，stony brook）
Geometric quantization for proper moment maps: the Vergne conjecture
Xiaonan Ma（麻小南 法国巴黎第七大学）, Weiping Zhang（张伟平 南开大学）
2013
p-adic logarithmic forms and a problem of Erdős
Kunrui Yu（香港科技大学）
2012
2011
2010
2009
The quantum orbifold cohomology of weighted projective spaces
Tom Coates, Alessio Corti, Yuan-Pin Lee（李元斌 犹他大学）, Hsian-Hua Tseng
（曾祥華 俄亥俄）
2008
Qu... 阅读全帖 |
|
L*m
发帖数: 235 | 23 统计了近十余年来中国大陆高校在四大刊物上的发文，有些是挂名的，但不管如何，还
是都统计了。全名单如下
Annals of Mathematics
A proof of Demailly’s strong openness conjecture
Qi'an Guan（关启安 北京大学） Xiangyu Zhou（周向宇 中科院）
A solution of an L2 extension problem with an optimal estimate and
applications
Qi'an Guan（关启安 北京大学） Xiangyu Zhou（周向宇 中科院）
Construction of Cauchy data of vacuum Einstein field equations evolving to
black holes
Junbin Li（黎俊彬 中山大学） Pin Yu（于品 清华大学）
Special test configuration and K-stability of Fano varieties
Chi Li(李驰 普林斯顿大学 现stony broo... 阅读全帖 |
|
K******S
发帖数: 10109 | 24 Scientist-Analytical Chemistry 23332BR :
The successful candidate will be part of an integrated team with
responsibility for various stages of LC-MS/MS assay development and
application in the quantization of drug and metabolite concentrations
in body fluids and tissue samples that will support clinical and
nonclinical pharmacokinetics studies. The position requires an
individual to be capable of using multiple instrument software
programs in the semi-automated preparation and analysis of sample |
|
d********m
发帖数: 2 | 25 arXiv:hep璽h/0212247
v1
19
Dec
2002
Comments On String Theory
Edward Witten
Institute for Advanced Study
Princeton, NJ 08540 USA
December 20, 2002
Abstract
String theory avoids the ultraviolet innities that arise in trying to
quantize gravity. It is also more predictive than conventional quantum
eld theory, one aspect of this being the way that it contributed to the
emergence of the concept of \supersymmetry" of particle interactions.
There are hints from the successes of supersymmetric unied th |
|
e**********n
发帖数: 359 | 26 cyclic is another way of saying periodic boundary condition, here Q is
identified with Q+2 pi.
Similar to crystal momentum, when the variable is periodic, its conjugate
momentum, which is the generator of its translation, has integer eigenvalues
. You probably need to familiarize yourself with Luttinger liquid theory in
1D before going to 3D solitons. There are lots of good tutorials on
Luttinger liquid on the web. |
|
n********s
发帖数: 150 | 27 Hi, eventhorizon,
Thanks a lot.I got it, and it makes sense to me now.
The Q is the charge of the soliton and it must be integer to any quantum
soliton. |
|
h******y
发帖数: 26 | 28 Some friend asked me the following question:
For a real scalar field \phi, assume that H = H_free - \int d^3\ x J \phi. J
(x, t) is just some real number, source, or background field, without second
quantization. Now, what is the amplitude \psi(x, t) for finding a particle
at time t(before, during, or after source is on/off) at position x? The J(x,
t) is nonzero only for finite period of time. And the initial state is
vacuum, when t --> -\infty
This question looks simple. However, I cannot find |
|
m**********e
发帖数: 12525 | 29 你去看functional quantization, page 282-292,
an introduction to quantum field theory
J
second
particle
x,
satisfie |
|
c****e
发帖数: 2097 | 30 You don't know Bryce DeWitt? Did you not read the very first serious
papers on canonical quantization of gravity? I thought those were
the 3 papers by DeWitt :D I guess you meant not to put those 2
brighter guys with Lee Smolin.
Lubos is probably right on many things, but apparently there's 1 LQG
speaker in strings this year. I just like to use my own judgement
instead of others, however it's hard to have time to go into that
literature, as it's pretty unenlightened.
I don't want to overstate it |
|
q*d
发帖数: 22178 | 31 agreed
有几本field quantization,relativistic quantum mechanics之类的
完全就Bjorken,Drell的照抄
百科全书一样的写一整套,自然是Landau的牛,
但学物理不该只看某一个人写的一整套书 |
|
C********n
发帖数: 6682 | 32
?
maxwell equations quantized
u got problem with that ? |
|
b********7
发帖数: 2404 | 33 >>不要见到 arxiv上的文章就上去啃
>>PRL上错的还不少呢
You are right.
>>
Just show it is still a topic how to quantize Maxwell electromagnetic field
for light (or light boson).
Dirac gave a good equation (Dirac equation) for electron (or fermion) many
many years ago. |
|
s*****i
发帖数: 467 | 34 Dec 14, 1900 – German physicist Max Planck presented a theoretical
derivation of his black-body radiation law, suggesting that electromagnetic
energy could only be emitted in quantized form.
zz From http://en.wikipedia.org/wiki/Main_Page |
|
b********y
发帖数: 41 | 35 麻烦发pdf到我邮箱 c******[email protected]
非常感谢！
Title: Topological invariant and the quantization of the Hall conductance
Authors: Kohmoto, Mahito
Publication: Annals of Physics, 160, Issue 2, p.343-354
Publication Date: 04/1985
Origin: ADS
DOI: 10.1016/0003-4916(85)90148-4
Bibliographic Code: 1985AnPhy.160..343K |
|
D******y
发帖数: 1296 | 36 Peskin
canonical quantization,QED,loop,renormalization,path integral formalism,
spontaneous symmetry breaking,YM
do all the homework in corresponding chapters
Chen and li
group theory,electroweak interaction,the SM
Srednicki (optional)
spinor technique
Peskin
R_xi gauge,Goldstone boson eq theorem |
|
m*******y
发帖数: 28 | 37 楼主能给些文献看看么？ 蛮好奇的。 我也看到过一些关于 在QCD中从Gauge
Invariance 和 canonical quantization的要求下推到出新的quark and gluon的角动
量，动量算符。也推广到了电磁场。 不过应该是蛮有争议的东西。但没看到过能量守
恒不守恒的文献，呵呵。电磁场中有个叫Hidden momentum 的概念。
100 |
|
N***m
发帖数: 4460 | 38 I think using the uncertainy principle here is the same
as using the Sommerfeld-Wilson quantization condition. For ground state
which is smooth and no inside node, you can always treat the integral
as something like average quantities, just as in the form of uncertainty
relation. There is no need for vague statements in your arguments.
The average x and p in the simple Hydrogen example turn out to be
in good agreement with the expected values.
a
and
considers
spread' |
|
k*********g
发帖数: 791 | 39 space and time 是自变量，怎么 quantize? |
|
j*********t
发帖数: 217 | 40 Quantization of Newton's Constant in Certain Supergravity Theories.
Edward Witten, Jonathan Bagger
Phys.Lett.B115:202,1982
多谢！ |
|
j*********t
发帖数: 217 | 41 Quantization of Newton's Constant in Certain Supergravity Theories
Edward Witten, Jonathan Bagger, (Princeton U.)
PRINT-82-0333 (PRINCETON), May 1982. (Published May 1982). 13pp.
Published in Phys.Lett.B115:202,1982. |
|
t**********m
发帖数: 205 | 42 Quantum Gravity Based on Mach Principle and Its Solar Application
http://vixra.org/abs/1101.0076
The starting point of quantum mechanics is the classical algebraic formula
connecting energy to momentum: energy is proportional to the squared
momentum. As a result, energy and momentum do not be treated equally. The
wave equation of quantum mechanics (a differential equation) results from
the replacement of the classical energy quantity with the derivative with
time and the replacement of the momen... 阅读全帖 |
|
Q******g
发帖数: 607 | 43 that's right. Coulomb gauge in QED is physical. of course, it's
mathematically harder and uglier to quantize it in this
non-covariant gauge. but it is doable. In fact, one can even do it
for QCD. It is much more uglier and complicated. One reference
for such kind of treatment is TD Lee's QFT book.
part
exis
the
sho
th
and
physi
spin |
|
t**********m
发帖数: 205 | 44 The joy of viXra
https://telescoper.wordpress.com/2011/05/19/
Posted in The Universe and Stuff with tags arXiv, astronomy, Cosmology,
Physics, scientific publishing, viXra on May 19, 2011 by telescoper
From time to time on this blog I post rants about the state of scientific
publishing, open access, the importance of the arXiv for astronomy and
cosmology, and so on.
This morning, however, I discovered an “alternative” side to the whole
business of online science, a site by the name of viXra. Mos... 阅读全帖 |
|
g****t
发帖数: 31659 | 45 【 以下文字转载自 Detective 讨论区 】
发信人: guvest (我爱你老婆Anna), 信区: Detective
标 题: 哪位能帮我下载一个论文吗?
发信站: BBS 未名空间站 (Wed Sep 7 21:45:22 2011, 美东)
Approximating a bandlimited function using very coarsely quantized data: A
family of stable sigma-delta modulators of arbitrary order, Annals of Math.,
158 (2)
annals.math.princeton.edu/wp-content/uploads/annals-v158-n2-p09.pdf
请发到z********[email protected],谢谢. |
|
l*******G
发帖数: 1191 | 46 http://www.ldolphin.org/gspeed.html
Faster than the Speed of Light?
Lambert Dolphin, Physicist
Superman was able to leap tall buildings in a single bound, he was more
powerful than a locomotive, and was said to be able to travel faster than a
speeding bullet.
The speed of a bullet (300-900 m/sec) is no big deal in these days of
supersonic aircraft and spacecraft. Yet our fastest space vehicles do no
better than one one-hundred thousandth (1:10-5) of the current speed of
light. Overcoming gravity... 阅读全帖 |
|
d*******g
发帖数: 208 | 47 在你举的例子，严谨的做法是做一个histogram，就可以看到几乎所有数据都集中在Q的
整数倍附近。顺便提一下，这也是发现一维系统里conductance quantization的实验所
用的方法。
大家可能都会遇到bad sample 或bad data point的时候，但删除data必须有客观原因
。象闻的文章里做statistical analysis，还主观的删除将近三分之一的点，根本就是
skew the statistics，谈何“老老实实”。
块" |
|
d*******g
发帖数: 208 | 48 在你举的例子，严谨的做法是做一个histogram，就可以看到几乎所有数据都集中在Q的
整数倍附近。顺便提一下，这也是发现一维系统里conductance quantization的实验所
用的方法。
大家可能都会遇到bad sample 或bad data point的时候，但删除data必须有客观原因
。象闻的文章里做statistical analysis，还主观的删除将近三分之一的点，根本就是
skew the statistics，谈何“老老实实”。
块" |
|
S****8
发帖数: 401 | 49 小弟是应用系做计算写code的，物理几个分支都涉及但都理解得不深刻，有个项目对半
导体器件要搞点底层建模，用到一些二次量子化的东西，于是去请教了两个物理系的
phd，结果貌似跟俺的理解半斤八两也问不出个所以然。
他们俩算物理系相对做的不错的了，说这些都是当年学过的，但如今做科研用不到。当
然也
可能是他们研究方向的问题，不过小弟想借此地问问各位科班出身的正规军，二次量子
化这种东西，是现在懂的人越来越少了吗？还是俺的层次问题。。。 |
|
|
