Designing energy-smart 3G base stations
Aug 1, 2007
By Tim Haynes Mobile consumers are now demanding bandwidths comparable to those that can be achieved in a fixed location. 3G networks based on W-CDMA, and other new...
Highly efficient amplifier shows the promise of Doherty architecture
Jun 1, 2007
By Christopher Burns The Doherty amplifier architecture has come a long way in the 70 years since it was conceived and has the potential to deliver the efficiency demanded by today's base station transmitters as well as those serving future generations of wireless networks. The Doherty amplifier described in this article is one of many designed at Freescale, which has been refining the basic Doherty concept....
Applying a high linearity variable gain amplifier
May 1, 2007
By Tuan Nguyen The high linearity variable gain amplifier VG025 is designed for use in transmitter and receiver automatic gain-control circuits, and as variable gain blocks following low-noise amplifier stages in high dynamic range receiver front-ends....
Using MCPAs as active combiners for optimizing the 3G transition
Apr 1, 2007
By Christopher Zappala and Jeffrey Strahler Wireless operators have used multicarrier power amplifiers to increase the coverage and capacity of existing base stations. Most often, the MCPAs have operated in TDMA and CDMA environments, and not in GSM systems, until recently. With active combining emerging as the MCPA's primary application, 3G networks are becoming the target for deployment. In addition to describing what is active combining, this article shows how MCPAs can help transition to 3G networks....
Designing broadband WiMAX PA using GaN power transistors
Feb 1, 2007
By Robert Therrien, Walter Nagy and Isik C. Kizilyalli In addition to investigating the performance and design benefits of using gallium nitride (GaN) power transistors in broadband WiMAX applications, this article also presents RF performance achieved with silicon substrate and plastic overmold packaging for these transistors....
Log amps and directional couplers enable VSWR detection
Jan 1, 2007
By Anil Rachakonda and Larry Hawkins In addition to signal distortions, inefficiency and standing waves, RF energy reflected by impedance mismatching between a transmission line and its load can also damage the signal source, such as a power amplifier....
GaN power transistors poised for growth, LDMOS promises to maintain lead
Jan 1, 2007
By Ashok Bindra, editorial director and Mark Valentine, technical editor While bringing the latest developments in gallium nitride (GaN) power transistors for microwave applications, this report sheds new light on the GaN market as this
technology moves toward production....
Successful LNA design involves performance trade-offs
Nov 1, 2006
By Thomas Baker While the low noise amplifier is a relatively simple design compared to other RF components in a cellular receiver lineup, the performance trade-offs it presents challenge the LNA application design engineer....
Measuring RF parameters in GSM/EDGE power amplifiers
Oct 1, 2006
By Antonio Eguizabal In this article, a method for conducting RF lab measurements is presented using commercially available test equipment and following common RF practices. Usually, this involves testing in four bands and two modes....
Products
Oct 1, 2006
AFIXM daughter card Radstone Embedded Computing has announced an addition to the AFIX (additional flexible interface Xtension) family of plug-on daughter...
