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32 items tagged "signal"
Related tags:
signal code [+],
service vulnerability [+],
kernel [+],
print [+],
local information [+],
information disclosure vulnerability [+],
signal generator [+],
germany [+],
generator [+],
transmission [+],
tool [+],
pal [+],
mpeg2 encoder [+],
microcontrollers [+],
dvb t [+],
clock reference [+],
christian daniel thomas kleffel [+],
chaos communication congress [+],
radio [+],
home [+],
arduino [+],
ac signal [+],
Wireless [+],
wireless signal [+],
waterfall [+],
visualizer [+],
visualization tool [+],
video [+],
usb joystick [+],
us patent application [+],
udo [+],
traffic lights [+],
tone generator [+],
thomas pfeifer [+],
summit [+],
sultan qaboos university [+],
strength [+],
spectrum analyzer [+],
spectrum [+],
signal strength meter [+],
signal generators [+],
sided pcb [+],
security works [+],
security [+],
scott [+],
room quality [+],
room [+],
rf signal [+],
repair [+],
railroad enthusiasts [+],
railroad [+],
quality [+],
protocol [+],
proper signal [+],
probe [+],
pc. he [+],
opamp [+],
morse code signal [+],
morse code [+],
monitor [+],
model aircrafts [+],
model [+],
misc [+],
microphone [+],
meter [+],
machine [+],
logic function [+],
logic [+],
leigh [+],
led [+],
laundry machine [+],
laundry [+],
kevin [+],
jammed [+],
ir detector [+],
interpreter [+],
home automation system [+],
heart rate monitor [+],
handhelds [+],
ham [+],
function generators [+],
function [+],
frank [+],
first glance [+],
fingertip [+],
equipment [+],
engineering [+],
dumpsters [+],
dumpster diving [+],
diy [+],
digital [+],
didj [+],
design upgrades [+],
debraj [+],
dcf [+],
control hardware [+],
clock signal [+],
clock [+],
classmates [+],
cascata [+],
capability [+],
canada [+],
cable side [+],
c synthesized [+],
c ppm [+],
braunschweig germany [+],
avr [+],
audio [+],
audacity [+],
atomic clock [+],
atmega8 [+],
arpad [+],
analyzer [+],
analog signal [+],
aircraft [+],
Support [+],
General [+],
BackTrack [+],
hacks [+],
linux kernel [+],
linux [+]
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12:01
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Hack a Day
[Udo] decided to build a clock using the DCF77 radio module seen above. This of course has been done before: the hardware draws a clock signal from the atomic clock in Braunschweig, Germany. So he grabbed a library for Arduino and got to work. But he was getting rather poor results and upon further investigation realized [...]
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11:19
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Hack a Day
We must be walking past the wrong dumpsters because we certainly haven’t encountered equipment like this just waiting to be salvaged. [Shahriar] found an HP 8648C Synthesized Signal Generator while he was ‘dumpster diving’ and set out to fix the malfunctioning lab equipment. He posted a 1-hour video on the project, which you can find embedded after the break. [...]
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21:31
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SecDocs
Authors:
Christian Daniel Thomas Kleffel Tags:
TV Event:
Chaos Communication Congress 23th (23C3) 2006 Abstract: As DVB-T is the key technology for terrestrial broadcasting for the next decades, this lecture tries to explain how it works: It covers the way of raw pixel data over MPEG2 video and audio encoding and via multiplexing of several streams and programs to the actual generation of the COFDM signal used for transmission. As the team has built a DVB-T transmitter, we will give a in-depth insight in how things are really done - including a demonstration of the transmitter. Analog PAL based TV transmission is no more - DVB has taken over in Germany. This should be legitimate reason to take a really deep look into how the new technology works and what needs to be done to get your own transmission into the air. The base for our lecture is a standard FBAS signal coming from a video camera. From there we will go with it through all the necessary stages of encoding, framing, multiplexing and modulating. First step is the A/D conversion of the picture and the sound. The resulting 240MBit/s stream is fed into the MPEG2 encoder where video and audio is encoded using the given parameters resulting in a bitstream of defined datarate. To achieve that, the video is divided into single blocks, movement relative to earlier and later frames is detected, and then the data is transferred into the frequency domain and then encoded. A relatively similar thing is done to audio: It is split into several frequency bands and for every band it is decided if the listener will hear this band or not using a psycho accoustical model. Then the remaining data is encoded into a bitstream as well. After that a program clock reference is generated to enable the receiver to keep video and audio in sync while playing back the stream. During the next stage, all video- and audio-streams are multiplexed into one big transport stream and several data tables are added. These tables define, which programs belong to this transport stream and assign video and audio streams to these programs. Electronic program guide and teletext are added and finally the COFDM modulator has the job to generate a base band signal for transmission. Here data is scrambled and interleaved several times, two types of forward error correction are added and then the bits are distributed to the up to 8000 distinct carriers which compose the final signal. As we have built a complete OFDM modulator we will then demonstrate how all these things work together and finally you will be able to watch our transmission using your own DVB-T stick.
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21:31
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SecDocs
Authors:
Christian Daniel Thomas Kleffel Tags:
TV Event:
Chaos Communication Congress 23th (23C3) 2006 Abstract: As DVB-T is the key technology for terrestrial broadcasting for the next decades, this lecture tries to explain how it works: It covers the way of raw pixel data over MPEG2 video and audio encoding and via multiplexing of several streams and programs to the actual generation of the COFDM signal used for transmission. As the team has built a DVB-T transmitter, we will give a in-depth insight in how things are really done - including a demonstration of the transmitter. Analog PAL based TV transmission is no more - DVB has taken over in Germany. This should be legitimate reason to take a really deep look into how the new technology works and what needs to be done to get your own transmission into the air. The base for our lecture is a standard FBAS signal coming from a video camera. From there we will go with it through all the necessary stages of encoding, framing, multiplexing and modulating. First step is the A/D conversion of the picture and the sound. The resulting 240MBit/s stream is fed into the MPEG2 encoder where video and audio is encoded using the given parameters resulting in a bitstream of defined datarate. To achieve that, the video is divided into single blocks, movement relative to earlier and later frames is detected, and then the data is transferred into the frequency domain and then encoded. A relatively similar thing is done to audio: It is split into several frequency bands and for every band it is decided if the listener will hear this band or not using a psycho accoustical model. Then the remaining data is encoded into a bitstream as well. After that a program clock reference is generated to enable the receiver to keep video and audio in sync while playing back the stream. During the next stage, all video- and audio-streams are multiplexed into one big transport stream and several data tables are added. These tables define, which programs belong to this transport stream and assign video and audio streams to these programs. Electronic program guide and teletext are added and finally the COFDM modulator has the job to generate a base band signal for transmission. Here data is scrambled and interleaved several times, two types of forward error correction are added and then the bits are distributed to the up to 8000 distinct carriers which compose the final signal. As we have built a complete OFDM modulator we will then demonstrate how all these things work together and finally you will be able to watch our transmission using your own DVB-T stick.
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21:31
»
SecDocs
Authors:
Christian Daniel Thomas Kleffel Tags:
TV Event:
Chaos Communication Congress 23th (23C3) 2006 Abstract: As DVB-T is the key technology for terrestrial broadcasting for the next decades, this lecture tries to explain how it works: It covers the way of raw pixel data over MPEG2 video and audio encoding and via multiplexing of several streams and programs to the actual generation of the COFDM signal used for transmission. As the team has built a DVB-T transmitter, we will give a in-depth insight in how things are really done - including a demonstration of the transmitter. Analog PAL based TV transmission is no more - DVB has taken over in Germany. This should be legitimate reason to take a really deep look into how the new technology works and what needs to be done to get your own transmission into the air. The base for our lecture is a standard FBAS signal coming from a video camera. From there we will go with it through all the necessary stages of encoding, framing, multiplexing and modulating. First step is the A/D conversion of the picture and the sound. The resulting 240MBit/s stream is fed into the MPEG2 encoder where video and audio is encoded using the given parameters resulting in a bitstream of defined datarate. To achieve that, the video is divided into single blocks, movement relative to earlier and later frames is detected, and then the data is transferred into the frequency domain and then encoded. A relatively similar thing is done to audio: It is split into several frequency bands and for every band it is decided if the listener will hear this band or not using a psycho accoustical model. Then the remaining data is encoded into a bitstream as well. After that a program clock reference is generated to enable the receiver to keep video and audio in sync while playing back the stream. During the next stage, all video- and audio-streams are multiplexed into one big transport stream and several data tables are added. These tables define, which programs belong to this transport stream and assign video and audio streams to these programs. Electronic program guide and teletext are added and finally the COFDM modulator has the job to generate a base band signal for transmission. Here data is scrambled and interleaved several times, two types of forward error correction are added and then the bits are distributed to the up to 8000 distinct carriers which compose the final signal. As we have built a complete OFDM modulator we will then demonstrate how all these things work together and finally you will be able to watch our transmission using your own DVB-T stick.
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15:01
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Hack a Day
At first glance you would think this is the real thing, but [Kevin] built this railroad crossing signal from parts you can find at the home store. We keep seeing traffic lights used as web-connected signaling devices. This would be right at home for that type of setup, but [Kevin] built it with railroad enthusiasts [...]
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4:01
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Hack a Day
[Scott] wrote in to us with his simple, but well done RF signal strength meter. As he points out in his post, sometimes an Arduino is overkill, so a Picaxe 08M was used instead. Apparently this was a refresh of a high school project that he did. Certainly many of us would have liked to [...]
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16:01
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Hack a Day
[Sulaiman Habsi] and two classmates put together a Morse Code interpreter as a class project at Sultan Qaboos University. The system listens to a morse code signal using a microphone, then translates that input to text which is displayed on this character LCD. The breadboarded circuit feeds an audio signal from the microphone, through an OpAmp, [...]
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11:01
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Hack a Day
It seems that [Limpkin] was up to no good this weekend. He decided to snoop around inside a smart-card laundry machine. He posted about his larceny adventure and shared the details about how card security works with this machine. We’re shocked that the control hardware is not under lock and key. Two screws are all that secures [...]
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12:01
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Hack a Day
While function generators or analog signal generators are ubiquitous in their utility, we haven’t seen much of logic function generators on Hack a Day. Luckily, [Dilshan] sent in a really neat 8-channel signal injector that is amazingly simple to build and comes with a great front end for editing patterns from your computer. The hardware portion of [...]
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11:01
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Hack a Day
[Arpad] has spent quite a bit of time reverse-engineering a home automation system, and, as he is quick to point out, presents the information learned for informational purposes only. He’s really done his homework (and documented it well), looking into the US patent application, and figuring out how the protocol works. If you’re wondering how [...]
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10:01
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Hack a Day
A signal generator is a handy bit of kit and with the right components, it’s pretty easy to build one. Fabricating a proper signal generator probe is another matter entirely. [Frank]‘s DIY signal generator probe does exactly what it claims to, and is very cheap to boot. After [Frank] made a simple signal generator with [...]
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5:01
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Hack a Day
[Leigh] is a HAM operator (you may know him as wa5znu). He is familiar with a signal visualization tool called a waterfall which plots signal strength and frequency over time. He wanted to build his own waterfall and ended up with this Arduino-based version which he calls Cascata. Cascata means waterfall in Italian which meshes nicely with Arduino’s [...]
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7:48
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Hack a Day
[Debraj] needed a simple signal generator for a project he was working on, but didn’t have one handy. He found that the easiest and cheapest way to get clean, reliable signaling was by using something that was already sitting on his desk – his PC. He found that the tone generator built into Audacity was [...]
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7:10
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Hack a Day
[Debraj] wrote to us describing a project he recently completed – a simple, compact spectrum analyzer using a 16-bit dsPIC microcontroller. The analyzer is fed an analog signal, which is passed through a large resistor followed by an opamp. A DC offset is then applied to the signal, after which it is passed through a [...]
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10:00
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Hack a Day
[Embedded lab] has a nice tutorial on building your own heart rate monitor. The monitor works by shining infrared light into the fingertip and looking at the changes in the reflected infrared signal caused by a heartbeat. The IR detector produces a very small AC signal so a couple of op-amps are used to filter and amplify the signal. [...]
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15:00
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Hack a Day
[Vassilis Papanikolaou] took a good thing and made it better with some design upgrades to this AVR based signal generator. We looked at version 1.0 of this tool back in 2006 and since then it saw an upgrade to 2.0. But [Vassilis] wanted to take things one step further, with a compact single-sided PCB. What [...]
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10:00
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Hack a Day
[Thomas Pfeifer] has taken the PPM signal produced by model aircraft wireless controllers, and with an ATMega8, converted the signal to act as a USB joystick. Which means you can now use a standard R/C remote control to fly model aircrafts on your computer. Of course now with PPM decoded you could also use the [...]
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13:00
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Hack a Day
[Nirvous] managed to get composite video out working on the DIDJ. He knew that the CPU had the ability to generate the signal, and that similar devices already had this capability. After studying some DIDJ teardowns he figured out which connection on the processor should provide the appropriate signal. Next was the firmware side of [...]
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16:57
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remote-exploit & backtrack
I have a X61s, and connected and disconnected the antenna at least 10 times, not more than 20-- and I currently get a weak wireless signal compared to other people (detail below). I am also running a X61s with some Lenovo software, so I'm not sure if the software is lowering the signal, but no matter what I do it still seems like I can't get it as high of a signal. Would removing the antenna connectors (cable at the 3945abg card) that many times damage it? I just bend the cable side up and the connector pops off.
As for low signal... I have a router running Tomato, and other computers in the same room get quality of ~60, and ~35-50 in the adjacent room (quality being dBi difference between noise floor and signal quality). However, my computer gets about 30-40 in room, and 10-20 in the adjacent room--and drops off much quicker a few rooms down.
If I want to fix it, what would I have to replace, or is there some other fix possible? (dip it in solder?)
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