l*******c
发帖数: 523 | 1 我还没弄好呢。今天忙娃忙了一天。
明天回去公司查查看cache。 现在用的是atmel的MCU.时钟是40MHz。 |
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c******k
发帖数: 1140 | 2 本人不是学电子的，近期要买示波器测 ultra short pulse.
center wavelength: 1550nm
Repetition rate: 40MHz
Pulse width: 100 Fs
请牛人解释一下什么样的示波器能满足我的要求？ 另外示波器面板上的4GHz和20Gs/S
是什么意思？多谢 |
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c******k
发帖数: 1140 | 3 我们有个FR－103XL autocorrelator。Femtosecond fiber laser 连接这个
autocorrelator，autocorrelator有个PMT探测器，它的输出接示波器，进而观察
autocorrelation signal,不知道买个什么样的示波器（多少带宽和采样频率）就够用
了？谢谢
超短脉冲信息如下：
center wavelength: 1550nm
Repetition rate: 40MHz
Pulse width: 100 Fs |
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f*****0
发帖数: 489 | 4 quite a few problems:
1) you don't need a virtual ground. since you are using four batteries, you
can just ground the circuit to the true ground - center of the batteries.
and if you really really want to use the virtural ground for whatever reason
, put a small eletrolytic cap on the resistor and lower their value to no
more than 1k.
2) you absolutely need to have power supply decoupling or your opamp will
likely oscillate. the particular opamp is a pretty fast one (40mhz gbp), so
you may want |
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s**********r
发帖数: 142 | 5 假设我的data rate 是1MHz
我的sampling rate是40MHz
不做任何filtering/average,我的error是多少？
是1M/40M 吗?
谢谢！ |
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s**********r
发帖数: 142 | 6 it is digital signal.
I am analyzing if there is any error from sampling frequency variation. My
DAC sampling frequency is 40MHz, is there any error if it varys from 41MHz
or 39MHz?
t |
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f*******t
发帖数: 49 | 7 就是单片机，内部时钟40MHZ， 25 ns.
只是感觉一个中断源，就1ms中断一次，来记录PULSE的输入，有没有更好的方式呢。
例如这里，2个SENSOR，就有2个中断源，各每1MS中断一次。 |
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b***i
发帖数: 3043 | 8 给你打了两次电话都没有人接，还是在这里讨论比较好，有多个人给你参考。
这个电路说简单也简单，说复杂也复杂，教授就是眼高手低。他自己做肯定做不出来。
8位没有问题，你到底什么精度的要求要说清楚。你内存给出32位的数然后4个一组进行
并串转换，就很容易得到8路的信号。这样150M也就需要150/4<40MHz的内存访问。我看
你直接用MCU去读内存都可以。要不用计数器什么的，Binary counter,比如MC10E016:
ECL 8-Bit Synchronous Binary Counter。不用串行并行转换，直接8位也可以。
用FPGA更适合。移位就是说你定义一个模块，有时钟输入，有reset输入，有输入端，
输出端，再加一个开关决定是从输出来循环到输入，还是从输入端读数。最后每个时钟
下进行移位，这个verilog最多20行程序完成。然后你把这个模块实例8个就是8位，根
本没有难度。你告诉教授你用SRAM+FPGA。然后你既可以完全用FPGA搞定，又可以用
FPGA+SRAM。
125MHz |
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w*******y
发帖数: 60932 | 9 Rosewill RNX-N180UB (1T2R) IEEE 802.11b/g/n USB 2.0 Wireless Adapter with
Hardware WPS Button
Up to 300Mbps Download Data Rates
Support 64/128-bit WEP (Hex & ASCII)
WPA/WPA2
WPA (TKIP with IEEE 802.1x)/WPA2(AES with IEEE 802.1x)
$24.99
-$13.00 Instant
$11.99
-$3.60 30% off w/ promo code [COUPON=32756]RWYEAREND[/COUPON], ends 1/6/12
$8.39
http://www.newegg.com/Product/Product.aspx?Item=N82E16833166049
Brand: Rosewill
Model: RNX-N180UBSpec
Standards:IEEE 802.11b/g/n
Wireless Data Rates: Up to 30... 阅读全帖 |
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f*u
发帖数: 5576 | 10 Tips: How to speed up wireless: Channel width set 40MHz; Encryption: TKIP/
AES
My N16 is stable at 300/150 for our three wireless laptops, the same as
E3000 2.4G band.
E3000 5G band is stable at 300/300, but only in short range, speed degradate
quickly through range.
I didn't notice any lag either N16(one year) or E3000(one month), they both
give me equivalent performance at 2.4G band.
N16 has huge 128MB ram over E3000 64MB ram; But unless you are goingto
install tons of stuff, the extra ram doe... 阅读全帖 |
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f*u
发帖数: 5576 | 11 April 5 update: replace RT-N16 with E3000, this guide still works
This is step by step dummy guide to install and config google voice in RT-
n16, there is also nonoh dialplan sample so you can set to make calls to
China.
It works perfectly with RT-N16, it may also work on other routers with some
modification.
You can make/take free phone calls through US and Canada through Gtalk directly,
sipgate, sipsocery, call parking etc are no longer needed :)
If you have nonoh setup, you can also dial 0118... 阅读全帖 |
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f*u
发帖数: 5576 | 12 Tips: How to speed up wireless: Channel width set 40MHz; Encryption: TKIP/
AES
My N16 is stable at 300/150 for our three wireless laptops, the same as
E3000 2.4G band.
E3000 5G band is stable at 300/300, but only in short range, speed degradate
quickly through range.
I didn't notice any lag either N16(one year) or E3000(one month), they both
give me equivalent performance at 2.4G band.
N16 has huge 128MB ram over E3000 64MB ram; But unless you are goingto
install tons of stuff, the extra ram doe... 阅读全帖 |
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g****n
发帖数: 3370 | 13 【 以下文字转载自 Hardware 讨论区 】
发信人: gqshen (香江游子), 信区: Hardware
标 题: 神由刷好了，有几个问题请教
发信站: BBS 未名空间站 (Fri Sep 9 23:23:47 2011, 美东)
之前在网上研究了一阵子，今天下午用了五分钟时间给神由刷上了神油dualwan,
用的是传说中的“轻抚菊花”法，简单快速。;) 有几个问题请教一下。
用Tomato已经好几年，所以界面不算陌生，只是中文版有些名词要稍微转个弯，
有些字体太小，其他都很自然亲切。第一感觉是多了很多东西（以前用的是1.27版），
尤其是QoS，有个“智能QoS“还有个“QoS设置“，这两个设置有重复吗？大家设置
一般用哪个？
第一次用Wireless N的路由，家里基本都是G的设备，我把无线网络协议设在自动，频宽
40MHz，控制边带高，WPA/WPA2 Personal, TKIP/AES，结果无线速率就在54Mbps, 这个
正常吧？试了试机器们倒是都能正常连上，除了x51v ppc连不上，它那里只有WPA-PSK，
TKIP, 不知道是不是这个原因。
还粗略试... 阅读全帖 |
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