Microwave Engineering Europe - May 2008 - (Page 25)

GPS & SateLLite 25 host processors in mobile phones, PDAs, personal navigation devices, and MP3 players. The GPS receiver is fabricated on low-power 90-nm RFCMOS technology and integrates a high performance baseband section with a low-noise CMOS radio front end. The chip uses a patentpending innovative RF design that improves both current consumption and LNA linearity as well as allowing for a minimum number of external components used. Further, low-power tracking at 15 mW ensures the longest possible battery life. PCB real-estate requirements are minimal, coming in under 35 mm2 for a complete Assisted GPS (AGPS) implementation. The chip features a realtime hardware correlator engine with fast acquisition and high-sensitivity that is capable of tracking 24 satellites simultaneously. Update rate is up to 2-Hz. Autonomous cold start time-to-first-fix (TTFF) is rapid at just 30 seconds. Products that include network connectivity, such as wireless PNDs and cellular phones, are able to exploit the full feature set of the BCM4750 software solution. These features include AGPS and long-term orbit (LTO) extended ephemeris assistance, reducing TTFF to less than one second in many conditions. The chip includes software that is optimized for cellular integration and the demands of international standards bodies — such as 3GPP and SUPL — that promote high speed data in cellular systems. The software includes message handling protocols for user and control plane-assisted GPS standards, as well as native support for LTO extended ephemeris service. In addition, the software has been optimized for personal navigation performance and includes sophisticated algorithms to mitigate multipath errors. A high –157-dBm assisted acquisition sensitivity (with coarse time assistance) and –162-dBm tracking sensitivity enable indoor and deep urban operation. Enhanced tracking sensitivity allows GPS-enabled mobile devices to detect very weak signals including those partially blocked or reflected by buildings or other structures. The chip exceeds 3GPP TS 25.171 and 3GPP2 TS C.S0036 performance requirements. Broadcom provides a software library that realizes the GPS navigation solution in the host using minimum resources and with no real time requirements. The company has pioneered the concept of host-based GPS, where the functionality is shared between the GPS IC and the host processor, as the best compromise for cost and size while maintaining performance in large volume mobile applications. Host-based GPS uses the GPS IC as a hardware accelerator that performs all the signal processing functions related to the acquisition and tracking of the GPS signals, relieving the GPS IC of a complete CPU subsystem including ROM, RAM, and other needed peripherals. Competing System-on-a-Chip (SOC) solutions often have navigation algorithms hardcoded in ROM, resulting in products that are quickly obsolete. Additionally, competing SOCs often use separate flash memory that call for multi-die systemin-package products that are bulkier and cost more than single-die solutions such as the BCM4750. Host-based architectures are ideal for AGPS products where various forms of aiding are used, since the aiding information typically comes from the host CPU. Requirements on the host CPU are minimum (few MIPS), and no real time requirements are imposed. Communication with the host is done through standard serial I/O protocols at very low bandwidth (down to 9.6 Kbps). RF testing out of control? Only Keithley gives you the RF test tools you need to rein in today’s devices and tame tomorrow’s challenges. MODEL 2920 RF SIGNAL GENERATOR MODEL 2820 RF SIGNAL ANALYZER n Test the most complex signal structures, including 802.11n WLAN MIMO and 802.16e Wave 2 WiMAX. Configure a 4x4 MIMO test system costeffectively. Generate and analyze signals up to 6 GHz repeatybly and accurately with our instruments’ software-defined radio architecture. Reduce your time to market and cost of test with MIMO systems optimized for R&D and production test. n n n Go to www.keithley.com/tame and try a demo. www.keithley.com/contact info@keithley.de Microwave Engineering ● May 2008 ● www.mwee.com http://www.keithley.com/tame http://www.keithley.com/contact http://www.keithley.com/contact http://www.mwee.com

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Microwave Engineering Europe - May 2008 News Contents Comment Cover Feature: How to Succeed as a GaAs Foundry Wireless Networking: Wireless Coverage Where Everybody WINS Wireless Networking: Achieving Good Coexistence in the 2.4 GHz ISM Band GPS and Satellite: GPS developments: Galileo Moves Forward with Successful Giove-B Satellite Launch — Broadcom Targets AGPS in Mobile Phones and Devices Raising the Bar for the Radio: Making 802.11n Work Reducing Power Consumption in Ultrawideband Chips WiMax Catches Second Test Wave Products Calendar

Microwave Engineering Europe - May 2008

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