o*******g
发帖数: 1300 | 1 To be successful in any career, you need to find your own niche and know how
to amplify your talents.
Each human trait probably is normally distributed with a small std-dev.
For example, Yao Ming is a 5-sigma taller than average people. Now imagine,
if Yao is a bio phd, will he be as successful? Most likely not, since his
biggest advantage, his height is irrelevant to bio research. Yao's parent
did not want him to play basketball since they feel that is a tough road,
but they were wrong. If yao |
|
o*******g
发帖数: 1300 | 2 Why applying your talents to the right field is so critical? Because in that
field, any edge in that talent will be amplified.
The industry is always searching for talents to exploit. However, due to the
normal distribution, each extra percent more talent can be 100% harder to
locate.
There are jobs probably needs a threshold of minimal talent to be good at.
For example for programming, let's assume you have to have an IQ of 120 at
least. For those people with IQ below 120 (think about GRE math |
|
j*****q
发帖数: 82 | 3 rt
how to amplify extreme AT-rich sequences on genomic DNA?
followed some literatures to decrease the enlongation temp. to 60 degree,
but still failed.
i am using the roche polymerase and qiagen one.
seeking for helps!
please!!! |
|
f****e
发帖数: 679 | 4 2nd this. The amplification efficiency of Taq drops sharply when the
amplified fragment is more than 6-7 kb. Phusion works ok for 10 kb, plus it
is fast, saves a lot of time. |
|
|
f*****0
发帖数: 489 | 6 it will depend on what amp you are talking about.
most people consider 驱动能力 to be a power amp's ability to drive low (
resistive) load. for audio amplifiers, that's the ability to drive a 2 ohm
or 4 ohm load, vs. a 8ohm load.
in most cases, it is determined by the output stage's ability to handle
large current. this is typically done with large power transistors, or large
die area for its output stage (paralleling multiple output devices).
sometimes, it is also the ability to drive non-resistive |
|
c*****i
发帖数: 11737 | 7 用运放作了个Differential Amplifier，但接上电源后在没有任何输入的情况下，
Output在示波器上显示上百KHz的正弦波或方波（有外接到运放上的电阻决定，随电阻
增大，又正弦波变成方波）。那位仁兄能说说这是怎么回事。先谢谢了。 |
|
f*****0
发帖数: 489 | 8 I cannot think of it as being terribly marketable, unless you go into the
esoterics.
Basically, the topology is a Lin 3-stage opamp: input stage (typically a
differential pair), VAS (typically SE), and output stage (complementary EF
current amplifier).
if you dive into it a little bit deeper, there are other types as well.
Check out Douglass Self or Sloan's books on audio power amps.
those amps cover about 99% of the amps in the market place today. the rest
falls into the following category:
a) |
|
s******e
发帖数: 2181 | 9 First of all, thank fku0000 to settle my power amplifier question.
Does there exist ultra frequency amplifer? I mean ranges from 0Hz to higer.
Since I want to receive respiration signals, whose frequency is normally 0.2
-0.5Hz.
I found the lowest frequency for TDAs is 10 Hz unfortunately. |
|
s******e
发帖数: 2181 | 10 ultra low frequency dosn't mean DC.
The human respiration frequency is very low - under 1Hz. Zero means the
person is dead! I don't want DC signal either.
What I need is to seek an amplifier whose frequency range covers 0.1 to 1Hz.
If I move away the input/output capacitoes of TDA circuit, DC component
will enter. |
|
s******e
发帖数: 2181 | 11 ultra low frequency dosn't mean DC.
The human respiration frequency is very low - under 1Hz. Zero means the
person is dead! I don't want DC signal either.
What I need is to seek an amplifier whose frequency range covers 0.1 to 1Hz.
If I move away the input/output capacitoes of TDA circuit, DC component
will enter. |
|
r******w
发帖数: 13 | 12 How about modulate the ultra low frequency signal to high frequency signal?
After amplified, demodulate the output signal and low pass filter it. |
|
c********g
发帖数: 421 | 13 我在用EG&G的lock-in amplifier测量 PZT材料的电压输出信号
测量电路和一些paper上使用的基本一致， 只是 device 不一样，output里只有一些读
数，
我不知道测量结果是否可信。
我一般都是选AUTO， 然后调一下AC Gain和Sensitivity
对Phase如何设置我还不是很清楚，好像对MAG没有什么影响。
请教有经验的太牛，怎样判断参数是调好了，结果比较可信？ |
|
c********g
发帖数: 421 | 14 没有人用过lock-in 吗？
我在用EG&G的lock-in amplifier测量 PZT材料的电压输出信号
测量电路和一些paper上使用的基本一致， 只是 device 不一样，output里只有一些读
数，
我不知道测量结果是否可信。
我一般都是选AUTO， 然后调一下AC Gain和Sensitivity
对Phase如何设置我还不是很清楚，好像对MAG没有什么影响。
请教有经验的太牛，怎样判断参数是调好了，结果比较可信？ |
|
f*****0
发帖数: 489 | 15
light (a
most TIA.
I am still unsure as to why you need a transimpedance amplifier.
I believe we call that a "resistor". |
|
w****j
发帖数: 237 | 16 请问一个简单问题：
一个depletion pHEMT QFN package MMIC amplifier (就是gate pinch-off是负电压的
pHEMT),在板子调试的时候好像drain current突然变大，立刻关了电源后，发现gate和
source的直流电阻用万用表测是33ohm,是不是以为着已经击穿了？？ |
|
s*****o
发帖数: 22187 | 17 不得不赞学习精神先，我明天有空也好好学习一下：）
amplif
amplifie |
|
h********t
发帖数: 555 | 18 答案很简单，你这里的主放大器是开环运行，其实根本就没有doublet的问题。
当然99%的情况下，主放大器将用于闭环运行。 在很多情况下，比如开关电容电路，反馈控制回路，通常希望 放大器能够快速 settle. doublet 会影响反馈系统的settling time.
doublet 是指 环路增益 (overall amplifier feedback loop gain) 的 零点和极点。零点当然来自于辅助放大器的 unit gain frequency。 极点 = Beta* gm1/CLoad
Beta 是主放大器用于闭环运行情况下的反馈系数。
具体设计，建议让辅助放大器的 unit gain frequency 不小于 2* Beta* gm1/CLoad
of |
|
l****o
发帖数: 184 | 19 忘记加图片了
。。
amplif
amplifie |
|
l****o
发帖数: 184 | 20 Very good point!
但是在output node of additional amplifier是不是会有一个pole呢？这个pole应该
会在closed loop -3dB frequency之内吧？
反馈控制回路，通常希望 放大器能够快速 settle. doublet 会影响反馈系统的
settling time.
。零点当然来自于辅助放大器的 unit gain frequency。 极点 = Beta* gm1/CLoad |
|
ET
发帖数: 10701 | 21
反馈控制回路，通常希望 放大器能够快速 settle. doublet 会影响反馈系统的
settling time.
。零点当然来自于辅助放大器的 unit gain frequency。 极点 = Beta* gm1/CLoad
而gain-boosting structure本来就是feedback 系统。
2-stage amplifier，用zero去cancel non-domaint pole，如果不能完全cancel，也算
一个doublet.
正因为cancel了，loop transfer function才看起来是single-pole roll off.
doublets的影响的确是在接成feedback（unite gain opamp)产生的。 建议让辅助放大
器的 unit gain frequency 不小于 2* Beta* gm1/CLoad |
|
l****o
发帖数: 184 | 22 I am also watching ucb ee240,在2007年leture 08里面 Dr.Alon 讲了不少关于gain
boosted amplifier的知识。
ee240确实不错啊，，埃，，可惜进不了berkeley |
|
ET
发帖数: 10701 | 23 没事。练手就该找难的练。
虽然不work的可能性也挺大。
回头移到90nm或更低了，会这个还是很有优势的。
gain-boosting的biasing network其实很麻烦，biasing main op-amp, biasing boost
ing amplifier. 一大堆transistors.
cmfb可能也是个问题。
你的main op-amp用的啥结构，telescopic 还是folded?
25ns,
design |
|
l****o
发帖数: 184 | 24 我用的dynamic cmfb,loop stability应该不是问题。
main op amp 我用的就是普通的one stage OTA with four addition amplifier to
boost the output impedance，Dr.Baker书上的一个结构。
boost |
|
y******n
发帖数: 67 | 25 这学期就要Phd毕业了，发个自己做的Matlab design tool for two-stage amplifier
by using inversion coefficient.
同时，也可以提提建议。
顶个马甲上来，如果有哪位在模拟ic设计公司，帮忙推荐一下。
程序在附件中，解压之后，在matlab里面运行 two_stage_design_tool.m |
|
|
T******n
发帖数: 3180 | 27 这类script，一般公司里都有
amplifier |
|
y******n
发帖数: 67 | 28 The design tool appearance.
amplifier |
|
ET
发帖数: 10701 | 29 有意思。。
啥是inversion coefficient?
amplifier |
|
y******n
发帖数: 67 | 30 这个东东还做不到自动设计，也就是实现用inversion coefficient的设计
方法在 two-stage amplifier design. |
|
y******n
发帖数: 67 | 31 谢谢大家关注，我做这个工具其实是为了验证一个idea，
算是为了发篇paper做的。现在把它拿出来放到网上，只是
现在找工作不顺利，希望能对找工作有点帮助。算是证明自己
对amplfiier设计还算认识比较深入吧。
运放的参数太多了，tradeoff太多，要真正做到自动化设计，
我觉得至少现在还没看到希望。
贴到这张图是用cadence来检验自己的idea和验证工具的精确性。
Design tool and SPICE predicted bandwidth product (GBW), phase margin (PM),
0.1% settling time (ST), current consumption, voltage gain, and slew rate (
SR) for the two-stage amplifier versus the M11 inversion coefficient IC11
where transistor drain currents change as needed to meet the specifications.
Solid l |
|
q*****z
发帖数: 191 | 32 Hi,
Not sure if this is the right place to ask this question.
I am trying to amplify a 0-1000 Hz sin signal to drive a 8 ohm EM load. Can
a class D handle the job?
I saw all the specs only go down to 20 Hz.
Also, I would like the output to be zero if the input is zero.
Anyboday familier with this subject?
Thanks a lot in advance. |
|
Y*****r
发帖数: 3 | 33 Is it a company? It's odd that I couldn't google anything on Quinlab
Amplifiers. Thanks~ |
|
b*******t
发帖数: 33714 | 34 我是说，你去查查你这个amplifier的spec
它的输出功率是100W，output impedance是50欧（输出你得连50欧的线，或者自己调整
load），这样输出电压到不了那么多伏。也就是说，最大输入1V的时候是达不到50dB放
大的，已经saturate了 |
|
b*******t
发帖数: 33714 | 35 二手仪器买来或者买前找找spec和manual
你的系统关心的第一件事情是频率范围，第二是最终接到transducer上的电信号需要多
大amplitude，看看amplifier的输出功率能不能支持。所谓50dB flat amplification
是放大小信号用的，在saturate之前可以做到输入信号的线性放大 |
|
m**a
发帖数: 464 | 36 各位大牛，求问一个pole怎么解。
电路很巧妙，推导了之后求transimpedance gain什么的都挺简单的，但我就是不会求
这个pole了。
原paper里只是直接说了一句3dB BW在(1+A)gm/C2.
有一篇斯坦福的论文引用了这篇文章，推了很复杂的一堆，我觉得应该没这么难呀，解
一堆二次方程什么的。
原paper：
B. Razavi, “A 622Mb/s 4.5pA/√Hz CMOS transimpedance amplifier,”
ISSCC Tech. Digest,San Francisco, CA, Feb. 7-9, 2000, pp. 162-163.
斯坦福的paper：
A 56MΩCMOS TIA for MEMS Applications
电路在附件
先说谢谢了 |
|
m*******n
发帖数: 5 | 37 他都说了是microwave是amplifier，mmwave和RF是一回事。也就是从100MHz-100GHz的
范围，都会有应用的。 |
|
w*******y
发帖数: 60932 | 38 Dell Home
Turtle Beach Ear Force X11 Amplified Stereo Headset with Chat
$50 - $15 Instant Savings
= $35 ($34 w/ DPA) + Free Shipping
|
|
|
w*******y
发帖数: 60932 | 40 Product Features
Gloss 3 tone sunburst finish
Maple neck w/ 22 fret rosewood fingerboard
3 single coil pickups
pack includes, guitar, 10 watt amplifier, strings, strap, cable and picks
5 way pickup selector switch
Fender Stratocaster electric guitar (3-tone sunburst), strings, picks, a
strap, Squier SP-10 amp, and a 10-foot cable.
Link:
http://www.amazon.com/Starcaster-Fender-Electric-Starter-Sunbur
|
|
w*******y
发帖数: 60932 | 41 I was just back at the World Music Supply site to check on my guitar order (
WIDLX Black burst arriving tomorrow!!!), and I noticed that they have a
pretty good deal on a Behringer V-TONE GMA106 Guitar Amplifier. Regularly
priced at $79.99, so over 60% off... Looks to be last years model that they
bought out at closeout prices, so this appears to be a pretty good price for
a quality practice amp.
Link:
http://www.worldmusicsupply.com/Behringer-V-TONE-GMA106-Guitar-
Shipping does add to it (looks... 阅读全帖 |
|
w*******y
发帖数: 60932 | 42 Behringer V Tone GMA106 10 Watt Electric Guitar Amplifier with Distortion -
Factory Buyout While Supplies Last
Sku # : GMA106
Manufacturer : Behringer
Mfg. Part # : GMA106
Stock : Available
List Price :
$119.99
Price :
$79.99
Sale Price :
$29.99
Link:
http://www.worldmusicsupply.com/Behringer-V-TONE-GMA106-Guitar-
|
|
|
|
d*****r
发帖数: 39446 | 45 【此篇文章是由自动发信系统所张贴】
amplifier 申请加入本俱乐部的请求已经通过审批, 成为本俱乐部的正式成员, 特此通知. |
|
d*****r
发帖数: 39446 | 46 【此篇文章是由自动发信系统所张贴】
amplifier 已经退出本俱乐部, 特此通知. |
|
d*****r
发帖数: 39446 | 47 【此篇文章是由自动发信系统所张贴】
amplifier 已经退出本俱乐部, 特此通知. |
|
d*****r
发帖数: 39446 | 48 【此篇文章是由自动发信系统所张贴】
amplifier 申请加入本俱乐部的请求已经通过审批, 成为本俱乐部的正式成员, 特此通知. |
|
d*****r
发帖数: 39446 | 49 【此篇文章是由自动发信系统所张贴】
amplifier 已经退出本俱乐部, 特此通知. |
|
d*****r
发帖数: 39446 | 50 【此篇文章是由自动发信系统所张贴】
amplifier 已经退出本俱乐部, 特此通知. |
|
