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ISSUE DATE: OCTOBER 2006 | |
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October 2006 - In This Issue [Cover Story] Signal Generator Melds Speed With Low Phase Noise Test-instrument manufacturers are faced with trying to provide performance that is one step ahead of emerging technologies. As difficult as this task may appear, many measurement equipment suppliers succeed by working closely with their device and component suppliers and their customers, keeping in tune with the latest test requirements. For frequency synthesizers, one of these requirements is fast frequency switching speed; another is low phase noise. Typically, it is difficult to find... — Ravinder Gill , et al. [News] Passive Components Stay On Path Of Re-Invention Passive components are the old, taken-for-granted workhorses of the high-frequency-electronics industry. The tasks that they perform, such as filtering and signal routing, are essential to both circuits and systems. Yet many are surprised to learn how much ongoing development is occurring in this area. New passive products are constantly coming out, thanks in large part to the spawning of new materials. Many of these product introductions are inspired by... — Nancy Friedrich [News] Making The Most Of Millimeter Waves Millimeter-wave frequencies have long represented untapped bandwidth. The cost of producing the components needed for transmitters and receivers, of course, has traditionally been one of the chief barriers to using millimeter waves for widespread communications systems. But Giga-Beam Corp. (Herndon, VA) has managed to assemble cost-effective millimeter-wave solutions with unique system architectures for those bands with the potential of providing OC-192-level performance at 10 Gb/s for... — Jack Browne [Design Features] Practical Approach Yields Class C PA Broadband Class C power amplifiers (PAs) are useful in certain communications bands. Although now integrated into the Advanced Design System (ADS) simulation software from Agilent-EEsof (www.agilent.com), the Touchstone simulation software at one time was a powerful tool for developing and optimizing impedance matching networks for such amplifiers. What follows is a design approach to show how to extract the optimum... — Firas Mohammed Ali [Design Features] Simplify The Calculation Of Microstrip Dimensions Circuit traces on microstrip printed circuit boards (PCBs) form the interconnections between components in addition to the components themselves. These controlled-impedance lines are typically designed with a characteristic impedance of 50 Ω for RF/microwave circuits or 75 Ω for cable television (CATV). The equations commonly associated with calculating the geometry of microstrip lines based on a desired impedance are quite complex and not easy to handle.... — Alberto Bagnasco [Design Features] Traffic Management Performs Testing For Triple-Play Services Triple-play telecommunications services—data, voice, and video—will add to the complexity of testing next-generation wireless system architectures. To handle this latency-sensitive traffic, emerging protocols and new hardware are needed that provide quality of service (QoS) via traffic management. Triple-play requirements are influencing network technologies like Universal Mobile Telecommunication System (UMTS), WiMAX, and digital-subscriber-line (DSL)... — Charlie Jenkins [Design Features] Develop Advanced Designs For RFID Transponders Radio-frequency identification (RFID) transponder design techniques were introduced last month, in the opening installment of this two-part article series. This month more advanced methods will be explored for enhancing the performance of UHF RFID transponders, using four design examples in Germany, the United States, Italy, and Switzerland. The German group was involved in pioneering work in UHF RFID, developing a variety of efficient circuit design techniques. However,... — Faisal Mohd-Yasin , et al. [Design Features] Design Directional Couplers For High-Power Applications Directional couplers are invaluable components for measuring the power levels of signals in microwave systems. Especially when high power levels are involved, a properly designed directional coupler provides a lower-power coupled signal that is within the power measurement range of a power meter or spectrum analyzer. By applying the finite-element method (FEM) of analysis, it is possible to effectively analyze and design asymmetrical rectangular (coaxial-microstrip and coaxial-stripline)... — Nasreddine Ben Ahmed , et al. [Product Technology] Spread-Spectrum Modules Communicate At 2.4 GHz Spread-spectrum technology was developed during World War II for the military, as a means of providing secure and reliable communications even in hostile environments. By 1980, the technology was approved by the FCC for use in industrial, scientific, and medical wireless applications in addition to military. The technology is now used for mission-critical and life-saving applications. There are a number of proprietary protocols and the standards-based protocols including... — Jack Browne [Product Technology] Real-Time Analyzer Captures Elusive RF Signals Spectrum-analyzer designers are faced with increasingly complex signals in modern radar and communications systems. As a result, today's spectrum analyzer is becoming more like an oscilloscope than the traditional swept-tuned instrument of years past. The latest Real-Time Spectrum Analyzers from Tektronix ( Beaverton, OR), the 9-kHz to 6.2-GHz model RSA6106A and 9-kHz-to-14-GHz model RSA6114A offer advanced triggering capabilities with the power of capturing instantaneous bandwidths as wide... — Jack Browne [Editorial] Gallium Nitride Finds Its Niche Over the past few years, more and more research and development has been devoted to gallium nitride (GaN). Many see GaN as the driver for next-generation high-frequency, high-power transistors— especially because it can operate at high temperatures. In the microwave market, many predict that GaN will be an almost ideal fit for mobile-infrastructure and WiMAX applications. GaN has a 3.4-eV band gap. Because of this wide band gap, GaN-transistor performance promises to remain... — Nancy Friedrich [White Paper] Improve The Accuracy Of Amplifier ACLR And ACPR Measurements The Agilent MXG vector signal generator (Fig. 1) produces the type of complex modulated signals found in modern digital wireless-communications systems, but without adding distortion of its own. The instrument is intuitive to use, allowing operators to modify key signal parameters "on the fly" locally or remotely. Ideally, the power amplifier in a wireless base transceiver station (BTS) would boost output... — Paul Schmitz |
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