IC Blog Center
Index 51
Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 5
Published:2011/8/18 2:35:00 Author:Amy
Stefan Tauschek More bandwidth This means we need more bandwidth and more channels. The standardization committee satisfied this need in 1999 with the introduction of the 802.1 la standard. It utilizes the 5.8-GHz ISM bond and employs a modulation technique called ’orthogonal frequency division multiplexing’ (OFDM). This yields o raw data rate of 54 Mbit/s, although the... (View)
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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 4
Published:2011/8/18 2:26:00 Author:Amy
Stefan Tauschek Wireless local area networks Now that you understand the techniques described above, we can enlighten you a bit regarding the various types of wireless networks currently in use. As can be seen in Figure S, frequency hopping is the technique used by (View)
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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 3
Published:2011/8/18 2:16:00 Author:Amy
Stefan Tauschek Code Division Multiple Access (CDMA) With the DSSS technique, frequency spreading is achieved by modulation using a pseudo-noise signal. This signal is also called the ’PN code’, since it identifies an individual transmitter just like an identification code. The information signal can only ... (View)
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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 2
Published:2011/8/18 2:08:00 Author:Amy
Stefan Tauschek Spread-spectrum techniques This problem can be solved relatively easily by taking a peek at the techniques used by (he military and copying their well-proven strategies. The magic word here is ’spread spectrum’, which amounts to modulating a narrow-band information signal in order to significantly increase its bandwidth while at the same time considerably r... (View)
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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 1
Published:2011/8/18 1:57:00 Author:Amy
Stefan Tauschek Wireless data communication is the latest rage. From wireless mice to Formula-] telemetry systems, digital radio systems are used in many applications, and they are penetrating into many new areas. In this article, we examine the current state of affairs in the ’airwave jungle’. The enormous popularity of wireless communication is a direct consequence or internation... (View)
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Elektor Junior Computer
Published:2011/8/18 1:23:00 Author:Li xiao na
By Jan Buiting Although the Elektor Junior computer was not the first home-built computer based on the 6502 processor (the KIM and others having achieved spectacular results in the USA) it did become a legendary design with PCB sales in the thousands. The original Junior Computer v/as designed b... (View)
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Power-Outlet LAN: In-home power lines carry audio and data
Published:2011/8/18 0:59:00 Author:Li xiao na
Jan Bulting Mains (or ’power-line’) signalling has matured from the early stages of the single 130-kHz carrier with simple modulation for a primitive 1-channel on-off control. Today, off-the shelf equipment is available that allows you to use the mains wiring and power outlets in your home or office to convey ... (View)
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Intelligent Clap Switch: manual remote control with extras （2）
Published:2011/8/17 22:42:00 Author:Li xiao na
Jorg Prim Software When the signal level at GP1 goes low (clap detected) the program waits for approximately 200 ms during which time the LED glows red. After this period the LED switches to green and the software samples the input for approximately three seconds. If a second clap is detected during this period, the (View)
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ANTI-NOISE （2）
Published:2011/8/17 22:36:00 Author:Phyllis
If passive ear protectors, such as earplugs or closed headphones, are combined with active noise compensation, noise in the frequency range from 25 Hz to 500 Hz can be attenuated by more than 25 dB (Figure 5). The total effect of active and passive noise compensation is around 30 dB over the entire audio spectrum. Closed systems are particularly suitable for aircraft with a high noise level in the ... (View)
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ANTI-NOISE （1）
Published:2011/8/17 22:20:00 Author:Phyllis
The sound of silence Noise has a serious impact on the environment as well as on human beings. Besides classical sound reduction techniques such as insulation, researchers are trying to attack the root of the problem using electronic means. They have already had some success. Sometimes it happens that an underlying physical process is well understood on paper, but the job of trans... (View)
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Altium FPGA LiveDesign Kit -Designing with FPGAs （3）
Published:2011/8/17 21:53:00 Author:Phyllis
By Paul Goossens Debugging The real power of the software is really only utilized when you want to carry out measurements on your design. It is obviously impossible to measure internal signals of the FPGA with a probe, so most examples are provided with a JTAG interface. With this you can (without di... (View)
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Altium FPGA LiveDesign Kit -Designing with FPGAs （2）
Published:2011/8/17 21:41:00 Author:Phyllis
By Paul Goossens Software The accompanying software is an evaluation version of the Protel/Nexar software suite from Altium. This version is time limited (30 days). Keep in mind that these 30 days start counting down from when the package is sent! It makes sense therefore, to install and try everything out immediately once you receive the package. This software looks very po... (View)
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Altium FPGA LiveDesign Kit -Designing with FPGAs （1）
Published:2011/8/17 21:31:00 Author:Phyllis
By Paul Goossens Modern circuits make ever more extensive use of FPGAs. Special software is required when designing with these devices. One of the companies that produce such software is Altium. In order to allow their software to be evaluated, they offer a cheap evaluation kit. Once the evaluation period has expired, the kit is still very useful as a development platform for your own desig... (View)
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PLAY SOLITAIRE .....packed in an AT90S micro （2）
Published:2011/8/17 21:17:00 Author:Phyllis
By Andy&Rose Morrell Rules for playing Solitaire As the name suggests, Solitaire is a game to be played on your own. The board is made up of 33 LEDs laid out in a cross shape, where a piece on the board (or ’peg’) is indicated by an active LED. The aim of this game is to be left with as few pieces... (View)
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PLAY SOLITAIRE .....packed in an AT90S micro （1）
Published:2011/8/17 21:03:00 Author:Phyllis
By Andy&Rose Morrell This version of Solitaire is played with an array of LEDs instead of pegs, with a microcontroller behind the scenes to check if you’re any good at playing. As you’ll soon find, the game is challenging and addictive! This project is a fine instance of a microcontroller and its residen... (View)
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The ScopeMeter 190 Series of Fluke
Published:2011/8/17 3:57:00 Author:Li xiao na
In the manufacture, distribution and service of the electronic test tools, biomedical equipment and networking solutions, the Fluke Corporation is the leading group all over the world. In order to analyze the signals better, Fluke has released the dual-input ScopeMeter 190 series of handheld oscilloscope. Wavefo... (View)
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Wond＇rous Light Chain
Published:2011/8/17 3:03:00 Author:Amy
With the Festive Season upon us, it seems fitting to devote this month’s Quizz’away instalment to the perennial problems associated with Christmas tree lighting. Conventionally, lamps are connected in series (Figure 1) and this immediately creates a problem: when one lamp fails, it breaks the series network and all other lamps will also go out. But that’s not all, because in the dark you will have hard ti... (View)
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LED Christmas Tree: Plus additional seasonal circuit
Published:2011/8/17 2:37:00 Author:Amy
This flashing LED mini only dead simple to build but the design is also repeatable and very reliable in operation. In fact an ideal last-minute project to brighten up the house or office in the run-up to Christmas. It can sometimes be satisfying for the electronics enthusiast to build something that adds a personal touch to a special occasion. The mini Christmas tree design described here fits the bill... (View)
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Intelligent Clap Switch: manual remote control with extras （1）
Published:2011/8/17 2:15:00 Author:Li xiao na
Jorg Prim A clap switch circuit is a classic beginner’s project. Equipment can be switched on and off by just clapping your hands. Add a tiny microcontroller and you can easily build-in some more useful futures. The microcontroller in this circuit makes it a simple job to add some useful features that are no... (View)
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Power Supply for USB Devices
Published:2011/8/17 2:00:00 Author:Amy
Roman Mittermayr More and more equipment is sold that runs off internal rechargeable batteries. Although a matching charger is usually supplied in the package, there are also devices that can only be charged via a USB port. That is not surprising in the case of USB MP3 players, which have to ’dock’ in the PC an... (View)
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