Project Solutions (2011/08/18)

OPAMP TESTER

Published:2011/8/18 22:39:00 Author:Phyllis

Quick go/no-go testing for operational amplifiers By Dirk Scheumacher Not a microcontroller in sight, and yet this item of test equipment will be found very handy in any elect...   (View)

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Playful Lights: Just there LEDs...

Published:2011/8/18 21:46:00 Author:Li xiao na

By hubert Marwald Here’s a recipe to make LEDs produce slow, continuous light effects rather than abrupt changes normally obtained from square-wave drive signals. If you are after really accurate control of one or more LEDs, the best option by far is pulsewidth modulation (PWM) which is usually obtained from a dedicated PWM chip or a suitably programmed microcon...   (View)

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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 7

Published:2011/8/18 2:49:00 Author:Amy

Stefan Tauschek Spatial multiplexing Antenna diversity is aimed exclusively at improving results at the receiver end, and it can be used even if the transmitter end has only one antenna. However, if multi­ple antennas are used al both ends of the path, even more refined technical tricks can be used to i...   (View)

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Wireless Connectivity: ISM, WLAN, WMAN, Bluetooth et al. 6

Published:2011/8/18 2:42:00 Author:Amy

Stefan Tauschek MIMO Increasing antenna gain by a few decibels is by no means the only trick that can be conjured out of the magic box of RF technology Multiple-input, multiple-out­put (MIMO) technology is also proposed as a means lo significantly increase range and data rates without increasing RF power. What lies behind this name is a sophisticated antenna technology called ’p...   (View)

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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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