Trends in Test part 4 – Explosion of wireless
05 May 2009
In the penultimate instalment, National Instruments looks at trends in test. This month focuses on the explosion of wireless.
We have previously looked at easier access to FPGA-enabled instrumentation, and how software-defined instrumentation combined with off-the-shelf multicore technology is enabling us to push the boundaries of the systems we deploy. Over the final two instalments of this series, we will continue to examine what can be done differently by discussing the explosion of wireless; and protocol-aware test.
Explosion of wireless
Rapid advances in RF and wireless hardware and the advent of more complex SoC devices have provided challenges for test engineers. Software-defined instrumentation will be increasingly important to address such challenges. For example, consumer electronics devices, including mobile phones and automotive in-dash entertainment systems, often integrate multiple communication protocols and standards such as GPS, WiMAX and WLAN. Test engineers using traditional instruments have to wait for a dominant standard to emerge and then for vendors to develop a dedicated, standalone box instrument to test that standard. With software-defined instruments, engineers can test multiple standards using common modular hardware components and implement emerging and custom wireless protocols and algorithms in their test systems regardless of the maturity of a new wireless standard.
The transition to software-defined instrumentation for all types of automated measurements systems, including RF, is expected to reach deployment of 100,000 PXI-based systems by the end of 2009, including more than 600,000 software-defined instrument modules. The use of open, user-defined software and modular PC-based hardware is ideal for automated RF test applications. In addition to software flexibility, it provides the highest-performance processors, flexible peripheral I/O, a compact modular design, and precise timing and synchronisation throughout the system.
In other words, the software-defined approach to automated RF test uses similar types of components to a traditional RF box instrument but applies them in a modular, user-defined architecture. This provides engineers with the highest-performance components, user-programmable I/O and analysis, and a compact form factor, with proven reliability in the most demanding RF test environments. The end reward for engineers thinking beyond the box is an RF test solution that is faster, more flexible, and equally accurate – all at a lower cost than stacking traditional RF boxes within a system.
Reduced measurement time
WLAN measurements such as error vector magnitude (EVM) and spectrum mask require a large amount of signal processing. Using multicore CPUs in PXI controllers, engineers can perform these measurements 5-10 times faster with software-defined RF instrumentation such as the NI PXIe-5663 6.6GHz RF Vector Signal Analyser (VSA). Moreover, engineers using the NI WLAN Toolkits for NI LabVIEW can automatically upgrade their measurement performance by benefiting from the advances in standard PC technology that PXI multicore controllers are based on, as these test libraries are designed for execution across multiple cores.
Increased flexibility
The modern smart phone often supports a minimum of six standards such as GSM/EDGE/WCDMA, Bluetooth, GPS, and even WLAN. With software-defined instrumentation, engineers can create any broadcast radio signal within LabVIEW and download it onto the memory of a PXI RF vector signal generator for immediate broadcast testing. For example, engineers from NI Select Alliance Partner, Averna, offer the PXI-based Universal Radio Tester (URT) to test multiple radio standards using the same modular RF instrumentation.
Accurate instrumentation
With software-defined RF instrumentation, engineers can achieve highly accurate measurements at a lower cost than traditional instruments. With the emergence of new wireless standards such as WiMAX and 3GPP LTE, many wireless devices must meet stricter RF performance requirements than ever before. For example, the minimum Error Vector Magnitude (EVM) requirement for an IEEE 802.11a/g (WLAN) transmitter is -25dB for the 54Mbps (64-QAM) signal type. Newer standards such as 3GPP LTE and WiMAX are subject to even higher RF performance requirements.
However, engineers today can obtain this level of accuracy for less using new PXI instruments such as the PXIe-5663 6.6GHz RF vector signal analyser and PXIe-5673 RF vector signal generator. Both instruments use the latest 16bit converters (ADCs/DACs) and a low-phase noise synthesiser (-110dBc/Hz at 1GHz) over wide instantaneous bandwidths (50MHz and 100MHz, respectively) to achieve accurate measurements at a lower price than the equivalent traditional box combination of a RF vector signal generator and analyser.
To further understand the benefits of software-defined instrumentation for RF, take a look at ni.com/rf
Tristan Jones is Technical Marketing Team Leader at National Instruments UK & Ireland
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