b***n
发帖数: 13455 | 1 it 号称它的input signal can be as small as -30dBm. 我们的一个SB 法国
Technical
Lead非说要达到它的这个要求而不用buffer...我说首先PLL里的frequency divider 用
dBm来度
量input signal level就是个weird的事; 还有这个-30dBm input 几乎可以肯定是还需要
buffer才能到divider input的... 欢迎大家谈谈... |
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I*********p
发帖数: 39 | 2 One of the three interviewers,a 装逼阿三,grilled me a lot,even though I gave
the correct answers, probably no hope for this position, hopfully the
following will help those who have the similiar background. Good luck.
1.Why FEM could fail on spurious emission?
2.GSM/CDMA frequency band, modulation scheme?
3.GSM conducted output power?
4.How to define TRP and TIS on a antenna, how to measure them?
5.If a GSM transmitter has conducted output 30dBm, antenna effiency is 50%,
what is its TRP? If directiv... 阅读全帖 |
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f****i
发帖数: 20252 | 3 显然是router和手机信号更强
基站是总功率大，但是稍稍拉开距离后功率就很小了，信号满格也就-50dBm左右
wifi信号满格的话估计要上-30dBm了 |
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B*****s
发帖数: 3463 | 4 请看楼上的回复，俺不知道哪个到底怎么运作的.
保守算法，每个每天通信3分钟，20户最理想的情况就是至少1个小时，
FCC 给的transmitter power 上限是1w/30dBm, 2.4G
2.4G 对砖墙水泥墙的穿透力很弱，穿过石膏板木板很容易，
接地金属板肯定是可以的.
对人体有啥影响不好说... |
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a******t
发帖数: 75 | 5 You may try to send a signal which is supposed to be in the image band.
Let's say the signal is at 1G+100MHz while the image should be in 1G-100MHz.
a CW tone with IQ phase will give you a output signal at 1.1GHz with a
power level 0dBm.
Now you shift the switch I Q input, such that I->Q, Q->I. The output signal
will appear at 900MHz, say, -30dBm power.
The modulator has an image rejection 30dB in this case.
Hope this is the answer you want.
check |
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h*****e
发帖数: 3 | 6 apoclypt的回答言简意赅，切中要害。找个人问问他们的经验值是多少，对于给定的
process和工
作频率，一般foundry会有一个Current Density Spec，单位一般是mA/um，如果这是DC
current，就用apoclypt的3倍经验值。
在假设VSWR=1的情况下，你的功率-电流的计算是对的，RF current没什么特别的，就
是频率高点
的AC current而已，别想得太复杂。高频引起的问题体现在skin depth上，趋肤效应引
发的后果
是等效横截面积变小，所以current handling的能力减弱。
这引发了一个悖论，因为apoclypt的经验值是相同的导体能够承受3倍的高频电流，这
里的原因是
AC current给了导体一个喘气的时间，不像DC current是持续加热。
你的问题很简单，对于30dBm的信号来说，基本上60um以上的线宽都可以handle。
Piggest写了一大堆，倒是把我给征服了。
2* |
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z*****n
发帖数: 7639 | 7 around 40dBm or 10W.
If you are 400m away from the BTS, you get approximately
-20 to -30dBm signal strength.
If you are close to a WIFI AP, you may get 100 times
stronger signal strength, or 0dBm. |
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d****6
发帖数: 971 | 8 我像猴子一样学着用spectrum analyzer,看到signal input口初写着max input 30dBm,
为啥
我测量的信号的channel power才10dBm， 屏幕上就喊着最后一级IF吃不消了什么的
外接的attenuator和内部的attenuator原理上到底有啥区别呢？外部的还好理解一些，
在信号被测
量前先通过一个attenuator，内部的attenuator值我手动调高之后观察到的现象是信号
幅度没变，
旁边的noise大幅增高了，想不明白
很菜的问题，描述的也很菜，还望多包涵 |
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b*********y
发帖数: 830 | 9 输出最好在30dBm以上，手机发射器用。
要求在600MHz到2.6G无条件稳定。
或者1.6G到3.2G稳定，高频段增益下降不要太厉害。
最好最大增益在增个频段内都要12dB以上。
我现在用的. ATF-511P8 ， 在1G以下不是无条件稳定， 在2.5G以上增益下降又太多。
我自己做一个简单的东西，实在不想弄加载什么的让他稳定了。
请大家推荐一个加上偏置，MN就能用的，各项指标符合要求的射频管。
提供有用信息的有包子。谢谢！ |
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x***y
发帖数: 830 | 10
需要
when you are getting -30dBm input, you probablly will see the frequency
division, but won't have rail to rail swing at output and your phase noise
will be degraded. |
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s******u
发帖数: 142 | 11 This guy tested the divider separately, so they use dBm for the input.
But it's weird for me to see a digital divider paper to put fig. 6, since
min input power vs. frequency curve is usually for ILFD. In a real PLL, you
will not get an input signal as small as -30dBm. Even if -30 dBm can work,
you don't need that small if you don't use the divider separately. |
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I*********p
发帖数: 39 | 12 One of the three interviewers,a 装逼阿三,grilled me a lot,even though I gave
the correct answers, probably no hope for this position, hopfully the
following will help those who have the similiar background. Good luck.
1.Why FEM could fail on spurious emission?
2.GSM/CDMA frequency band, modulation scheme?
3.GSM conducted output power?
4.How to define TRP and TIS on a antenna, how to measure them?
5.If a GSM transmitter has conducted output 30dBm, antenna effiency is 50%,
what is its TRP? If directiv... 阅读全帖 |
|
f*******y
发帖数: 32 | 13 抛砖引玉~~~
如果用FREE SPACE LOSS 公式L=(\lambda/4/pi/d)^2, where
\lambda=3e8/0.7e9, and d=sqrt(547^2+(269/3.3)^2)=553, 计算L大约等于80dB 衰
减。 基站功率为30+10*log10(75)大约为50dBm, 接收到的信号为-30dBm,远小于家里
WIFI的功率。 |
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z*****n
发帖数: 7639 | 14 ISM band 用到了55dBm？犯法了吧？我记得在915MHz里面
用了 spread 技术后可以到30dBm，如果是non-spread，好像
只能到0dBm? |
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w*******y
发帖数: 60932 | 15 Link:
http://www.amazon.com/gp/product/B005FYGEII
USE PROMO CODE 15DISCNT
this one does not have the carrying case and sells for $37.99 so i guess
this is a good deal
Link:
http://www.amazon.com/gp/product/B002BFMZR8
The Alfa AWUS036H is the latest version of the most powerful card available.
This has a stunning 1000mW output power. So if you are looking for a device
to connect to an outdoor 2.4 GHz antenna, such as on a boat or an RV, this
is a perfect solution. It outperforms wireless cards th... 阅读全帖 |
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w*******y
发帖数: 60932 | 16 Link:
http://1saleaday.com/
here is the Amazon link (it sells for $29.99) For review references
Link:
http://www.amazon.com/gp/product/B000QYGNKQ
The Alfa AWUS036H is the latest version of the most powerful card available.
This has a stunning 1000mW output power. So if you are looking for a device
to connect to an outdoor 2.4 GHz antenna, such as on a boat or an RV, this
is a perfect solution. It outperforms wireless cards that are built in to
newer laptops. Adding this to your laptop or desktop... 阅读全帖 |
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