Enchanter Space Studio: September 2010

Saturday, September 18, 2010

Set PDF print for Cadence IC5141 in Ubuntu 9.10

Add this to the .cdsplotinit:

CUPS_PDF|PDF:\
:spool=lpr -PPDF: \
:query=lpq -PPDF: \
:remove=lprm -PPDF $3: \
:manufacturer=Generic CUPS-PDF Printer: \
:type=postscript2: \
:resolution#600: \
:maximumPages#50: \
:paperSize="A4" 4758 6846 90 90: \
:paperSize="A3" 6846 9720 90 90:
:paperSize="A" 4800 6300 150 200:
:paperSize="A" 4902 6402 99 99: \
:paperSize="B" 6402 10002 99 99:

Friday, September 17, 2010

分贝表示的放大倍数 ----- 增益

分贝就是放大器增益的单位 --- dB ，放大器输出与输入的比值为放大倍数，单位是“倍”，如10倍放大器，100倍放大器。当改用“分贝”做单位时，放大倍数就称之为增益，这是一个概念的两种称呼。

dB 的两个定义方式：

电压（电流）放大倍数分贝数定义：K=20lg( V0 / Vi )，其中K为放大倍数的分贝数，Vo为放大信号输出，Vi为信号输入；

功率放大倍数分贝数定义：K=10lg( P0 / Pi )，其中K为放大倍数的分贝数，Po为放大信号输出，Pi为信号输入；

（K>0说明信号被放大，K=0信号直通，K<0说明信号被衰减）

分贝数值中，－3dB和0dB两个点是必须了解的。

关于－3dB带宽

－3dB也叫半功率点或截止频率点。这时功率是正常时的一半，电压或电流是正常时的0.707。在电声系统中，±3dB的差别被认为不会影响总特性。所以各种设备指标，如频率范围，输出电平等，不加说明的话都可能有±3dB的出入。

随着输入频率上升，放大电路的电压放大倍数将下降，当电压幅度降至最大值的0.707倍时的位置，为截止频率。这时功率值恰好是最大功率的一半所以又称为是半功率点。
用分贝表示正好下降了3dB（根据电压幅度计算： 20log(0.707)=－3dB
根据功率计算： 10log（0.5）=－3dB ），对应的频率称为上截止频率，又常称为-3dB带宽。

关于0dB

0dB表示输出与输入或两个比较信号一样大。分贝是一个相对大小的量，没有绝对的量值。可您在电平表或马路上的噪声计上也能看到多少dB的测出值，这是因为人们给0dB先定了一个基准。

例如声级计的0dB是2×10－4μb(微巴)，这样马路上的噪声是50dB、60dB就有了绝对的轻响概念。常用的0dB基准有下面几种：dBFS——以满刻度的量值为0dB，常用于各种特性曲线上；dBm——在600Ω负载上产生1mW功率(或0.775V电压)为0dB，常用于交流电平测量仪表上；dBV——以1伏为0dB；dBW——以1瓦为0dB。

不管是振幅类还是平方项，变成分贝后它们的量级是一致的，可以直接进行比较、计算。放大器级联时，总的放大倍数是各级相乘。用分贝做单位时，级联放大器的总增益就是相加。

Cadence File Locking Problems

This page describes fixes to file locking problems in Cadence.

Common File Locking Errors:

When cadence is not exited properly, there might be file lock problem when
you restart icfb. The error messages might look like this:

>*WARNING* Couldn't get a write lock for
>"/home/bisc/a/other/cadence/national/cmosx/jupiter27/j27_xjw/PFMclk/layout/layout.cdb"
> (clscompatd): Requested lock conflicts with active lock
>*WARNING* XXopen: failed to lock file
>/home/bisc/a/other/cadence/national/cmosx/jupiter27/j27_xjw/PFMclk/layout/layout.cdb
>in A_MODE mode - is currently not locked.

How to Fix the File Lock:

What can be done to remove file lock:

Use clsAdminTool to release active locks. type "clsAdminTool" to start,
then type "help" and follow the instructions.
This can also be done manually by deleting all .cdslck files under your
locked-file directories.
After 1 or 2, sometimes icfb still complains about file lock. try exit
cadence and kill all cadence processes, then restart icfb.
If after 1, 2 and 3, you still have the same file lock problem, it
could be a proxy lock (the warning message looks all the same). contact
system administrator to restart file-locking daemon (cdsd).

Thursday, September 16, 2010

Using IPW3945 instead IWL3945 for Intel wireless 3945 in hardy

while i’m using my dell d620 with an intel wireless 3945 card i have the following problems with hardy and the new iwl3945:

-throughput is limited 110kb/s rx
-the wireless lan is very unstable
-sometimes the system freezes while scanning for networks

i tried some things to workaround:

- installed the ubuntu-backports (so the driver 1.2.25 is install) = ok the wlan led works again
- add the file /etc/modprobe.d/iwl3945 (alias wlan0 iwl3945
options iwl3945 disable_hw_scan=1)
- to config the card i used wicd (wicd.sourceforge.net)instead of the builtin network-admin

now i decided to backport to the old ipw3945 driver which has do everything fine in gutsy…

1. sudo vim /etc/modprobe.d/blacklist

added the lines
# blacklist new iwl3945
blacklist iwl3945
blacklist mac8021

so the new iwl3945 won’t load at system startup

2. Reboot

3. Download ipw3945 microcode (http://ipw3945.sourceforge.net) and copy it into /lib/firmware/2.6.24-17-generic/

4. Download ipw3945 regulatory daemon from here and copy it into /sbin/
(copy the file within folder x86 to /sbin/ too)

5. get the patch from here thanks

6. get the ipw driver http://ipw3945.sourceforge.net/#downloads

7. patch -p1 <> (target file = ipw3945.h)

8. make

9. sudo make install

10. sudo chmod 777 /sbin/ipw*

11. add a file /etc/modprobe.d/ipw3945
add lines:
install ipw3945 /sbin/modprobe -i ipw3945 ; sleep 0.5 ; /sbin/ipw3945d –quietremove ipw3945 /sbin/ipw3945d --kill ; /sbin/modprobe -r -i ipw3945

12. sudo modprobe ipw3945

13. reboot

在Ubuntu里使用Windows的无线网卡驱动程序

1、准备好无线网卡的Windows驱动程序，我是用for Windows XP的。

2、先用有线网络联网，在新立得软件包管理器里安装ndisgtk。
或到 http://packages.ubuntu.com 下载ndisgtk、ndiswrapper-common和ndiswrapper-utils这三个.deb文件。然后按如下顺序安装这三个软件包：先装ndiswrapper-common，再装ndiswrapper-utils，最后装ndisgtk。

3、ndisgtk安装成功后，从菜单“系统——系统管理”中打开“Windows无线驱动程序”。点“安装新的驱动程序”。

4、选择无线网卡Windows驱动程序中的.inf文件。点“安装”。

5、可能会弹出提示说“不能确定硬件是否存在”，点“确定”。

6、然后在“当前已经安装的Windows驱动程序”列表中出现无线网卡的驱动，并显示“硬件存在：是”。点“关闭”。

7、这样就安装完成了。再点屏幕右上角的网络管理器，就能找到无线网络了。

本文地址：http://ubuntuabc.com/123/?p=26 来自：UbuntuABC

Tuesday, September 14, 2010

Add PPA Key To Your Apt Keyring

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys

Wednesday, September 8, 2010

如何设置ubuntu下的empathy登录qq

将qq2005改为qq2008。

Resolving Emacs "murrine_style_draw_box: assertion `height >= -1'"

Modify the entry in /usr/share/themes/Ambiance/gtk-2.0/gtkrc from GtkRange::trough-under-steppers = 0 to GtkRange::trough-under-steppers = 1.

Original Article: http://thehacklist.blogspot.com/2010/06/resolving-murrinestyledrawbox-assertion.html

Enchanter Space Studio