Next generation wireless tests
06 August 2008
RF technology is everywhere, and all signs point to the integration of more wireless devices in the future
Many wireless devices are used every day. From the IEEE 802.11a/b/g/n transceiver providing Wi-Fi on a laptop to the 49.82MHz FM transmitter in a baby monitor. From the RDS/DAB radio and GPS navigation in a car to a Bluetooth transceiver used to interface with the most common wireless technologies, mobile phones, RF technology is all around us.
This explosion of wireless adoption is driving the need for a new approach to wireless device design and test.
Two developing industry trends are an increasing number of devices that incorporate multiple standards, and the growing complexity of SoCs. To address these issues, National Instruments provides a single graphical system design platform based on NI LabVIEW, PXI Express RF modular instrumentation, NI TestStand, and parallel chip technologies such as multi-core processors and FPGAs.
Multiple protocols
Devices that integrate multiple communications protocols, such as GSM, EDGE, WCDMA and WLAN, are becoming ever more common. To keep pace, engineers can use a software-defined approach to test
wireless devices.
Using algorithms based on LabVIEW and the NI Modulation Toolkit, it is possible to perform custom physical layer measurements. Systems based on LabVIEW offer the ability to use the same PXI-based
system to test different standards by reconfiguring the measurements in software.
LabVIEW 8.6, released this month, provides numerical analysis libraries that are now multi-core enabled, further speeding-up mathematically intensive algorithms.
SoC complexity
The adoption of SoC architectures has led to the integration of many more components on a single RFIC (radio frequency integrated circuit). Some vendors have adopted custom digital baseband interfaces for
communications between baseband processors and RFICs. Others employ standards such as DigRF.
The challenge of complex communication protocols such as DigRF, is that ‘digital handshaking’ between the baseband processor and SoC is required. To meet this demand, the latest release of LabVIEW
offers users access to graphically programmable FPGA hardware, such as the PXI R series devices equipped with Xilinx Virtex-5 FPGAs.
Providing fast execution because they are inherently parallel, FPGAs also allow for custom timing and triggering. LabVIEW 8.6 offers hardware accelerated mathematical operations via new FPGA IP such as FFTs and rapid FPGA application debugging via a PC-based simulation mode.
Lowering the cost of test
Despite devices becoming more complex, margins are slimmer, manufacturing volumes have increased, and so has the pressure to reduce the cost of test. An effective way to do this is to reduce test time by adopting the latest, low-cost commerical technologies, including multi-core processors, FPGAs and high-speed PCI/PCI Express data buses. The PXI test platform incorporates these technologies, which can help to create high-performance test systems capable of parallel processing and parallel measurements (see figure 1).
To illustrate the performance of the NI parallel test platform, consider a basic WCDMA (wideband code division multiple access) test sequence on either the latest 6.6GHz PXIe-5663 RF signal analyser or
traditional instruments. The NI test platform delivers up to a x6 improvement in measurement speed, which could result in financial savings for the user.
RF automated test applications require increasingly fast measurements without sacrificing measurement accuracy. With the new PXI RF measurement platform, it is possible to address the increasing need to lower the cost of test.
www.ni.com/rf or www.ni.com/labview.
DAVID HALL is worldwide RF and wireless communications product marketing manager, National Instruments
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