用过模拟老电视的同学应该都对这个有印象。PAL （Phase Alternating Line）逐行倒相是一种模拟电视广播信号的调制方式，对应的还有NTSC（以National Television Standards Committee，国家电视系统委员会缩写明明的制式，一看就知道是老美的），和SECAM（Sequentiel Couleur A Memoire，塞康，顺序传送彩色与存储，顺序与存色彩电视系统），不过现在已经不多见了，因为模拟广播电视已经普遍被DVB（数字广播电视）所取代了。
看到PAL，又勾起了一些往昔学习信号与系统以及通原时的记忆：DSB，SSB，VSB……
UTC授时信号
UTC的全称是协调世界时系统。采集的这个信号发自于美国的NIST (National Institute of Standards and Technology) 。
[2015-12-10 12:20:34] Server INFO Dataset: in-memory
[2015-12-10 12:20:34] Server INFO Fuseki 2.3.0 2015-07-25T17:11:28+0000
[2015-12-10 12:20:34] Config INFO FUSEKI_HOME=/usr/local/apache-jena-fuseki-2.3.0
[2015-12-10 12:20:34] Config INFO FUSEKI_BASE=/usr/local/apache-jena-fuseki-2.3.0/run
[2015-12-10 12:20:34] Servlet INFO Initializing Shiro environment
[2015-12-10 12:20:34] Config INFO Shiro file: file:///usr/local/apache-jena-fuseki-2.3.0/run/shiro.ini
[2015-12-10 12:20:34] Config INFO Template file: templates/config-mem
[2015-12-10 12:20:36] Config INFO Register: /ds
[2015-12-10 12:20:36] Server INFO Started 2015/12/10 12:20:36 CST on port 3030
Softwear Defined Radio（软件无线电）并不是一个全新的概念，摘句百度百科上通俗的概括：“软件无线电利用现代化软件来操纵、控制传统的“纯硬件电路”的无线通信技术。其重要价值在于：传统的硬件无线电通信设备只是作为无线通信的基本平台，而许多的通信功能则是由软件来实现，打破了有史以来设备的通信功能的实现仅仅依赖于硬件发展的格局。软件无线电技术的出现是通信领域继固定通信到移动通信，模拟通信到数字通信之后第三次革命。” SDR是不是数字通信革命的方向，会不会带来深远的影响，这些并不是这次讨论的主题（一家之言也没有什么意义）。这次，我们只把目光放在眼前，从兴趣出发，该怎么调戏SDR呢？
$ kal error: must enter channel or frequency kalibrate v0.4.1-rtl, Copyright (c) 2010, Joshua Lackey modified for use with rtl-sdr devices, Copyright (c) 2012, Steve Markgraf Usage: GSM Base Station Scan: kal <-s band indicator> [options] Clock Offset Calculation: kal <-f frequency | -c channel> [options] Where options are: -s band to scan (GSM850, GSM-R, GSM900, EGSM, DCS, PCS) -f frequency of nearby GSM base station -c channel of nearby GSM base station -b band indicator (GSM850, GSM-R, GSM900, EGSM, DCS, PCS) -g gain in dB -d rtl-sdr device index -e initial frequency error in ppm -v verbose -D enable debug messages -h help
It happens sometime that the application window goes off screen. And the situation is pretty annoying since all the usual method will not pull the window back to the screen.
But as long as you can see the window, i.e. at least, the edge of the window, the following trick may help you to bring it back to your desktop:
move the mouse to the edge of the window, horizontal or vertical edge will do. By doing so, you will the see the pointer of the mouse changed to the horizontal or vertical adjust mode.
If you place the mouse on the horizontal edge, then, press the left button. BUT, rather than move the move up and down to adjust the height of the window, you move the mouse horizontally.
When you see the window start to move, keep the left mouse button pressed, and move the mouse in any direction, the window will now move with your mouse. And now, pull it back to the screen
Similarly, if you placed the mouse on the vertical edge, press the left button and move vertically first, after the window starting to move with your mouse, you are free to move it to any place you want.
There is another alternative:
move the mouse to one of the 4 corners of the window. You will see the pointer of the mouse changed to scaling adjust mode;
press the Option key, and press the left mouse button. Then move you mouse.
The window should scale in all directions with your mouse now.
Scale the window size, until you can see the title bar of the window. Done.
，天线接收信号
，输出的数据流的速率是
，模块A要把这个数据流作为输入送入模块B，那么至少要保证
是一样的。换句话说，我们要使模块A的输入数据流的速率
，在经过模块A处理变成速率为
。
和
，在模块A上对输入数据序列进行抽取，使速率下降为原来的
，之后再用内插数据点的方式，使输出的数据速率增加到
)，设置Interpolation为1(
)，这样输出的速率就变成：
