test&measurementZONE Products for the week of September 17, 2007

Agilent Technologies Says…

One-Box Wireless Networking Test Set for Mobile WiMAX Applications
Product Extends Unmatched Portfolio of WiMAX Measurement Solutions for R&D, Verification and Manufacturing

Agilent Technologies Inc. introduced a wireless networking test set and OFDMA measurement application software, forming a complete one-box transmitter and receiver test solution for Mobile WiMAX devices. With its superior specifications and fast manufacturing test time, this solution effectively meets the needs of cell phone, ODM and CM manufacturing engineers testing WiMAX mobile subscriber devices or modules that use IEEE 802.16e-2005.

In today's manufacturing environment, engineers are constantly faced with time-to-market pressures. They must get their products to market ahead of the competition, while at the same time protecting profit potential and ensuring the shortest possible test times. Additionally, testing high volumes of Mobile WiMAX devices requires a standard-compliant 802.16e-2005 physical layer test tool. Agilent's new N8300A one-box parametric WiMAX test set provides just such a solution to address these challenges, while the associated Agilent N6301A Measurement Application ensures fast and accurate measurement analysis of Mobile WiMAX signals.

"Agilent continues to demonstrate its leadership in the Mobile WiMAX arena via the rollout of industry-leading test and measurement solutions like the N8300A and N6301A," said Niels Fach, vice president and general manager of Agilent's Mobile Broadband Division. "That leadership and continued research and development of innovative measurement solutions fully enables engineers to rapidly and confidently design and implement high-quality radio systems, while also clearing the way for successful evolution and deployment of Mobile WiMAX."

The Agilent N8300A Wireless Networking Test Set is based on an architecture that integrates Agilent's state-of-the-art Vector Signal Analysis and Vector Signal Generator hardware, and features an easy-to-use front panel graphical user interface and SCPI command set. Measurement algorithms and software leveraged from WiMAX R&D test tools enables fast test development and measurement traceability through the product lifecycle.

"These new products complement Agilent's portfolio of WiMAX test solutions, which span the entire WiMAX lifecycle, from R&D through manufacturing," said C.J. Meurell, European operations general manager for Agilent's Mobile Broadband Division's WiMAX portfolio. "Their superior performance and benefits are further evidence of our commitment to continually updating our Mobile WiMAX measurement solutions to keep pace with evolving engineering requirements."

EN-Genius Says…

Anything that can make OFDMA (orthogonal frequency-division multiple access) air-interface test gear easier to use -- and provide meaningful information quickly -- is a boon to designers grappling with choosing devices at the component level, or wireless developers deploying full-blown systems.

Agilent’s test set debuts at a time when Mobile WiMAX (Worldwide Interoperability for Microwave Access) is just taking off. But, some industry watchers predict Mobile WiMAX will grow at a compound annual rate exceeding 50% through 2011, with systems being deployed not only here in the US, but in Europe, India, Puerto Rico, Russia, and South Korea, to name just a few.

Opportunity Knocks
As you might guess, Agilent Technologies is positioning itself nicely. For one thing, it’s a member of the WiMAX Forum, and the company has been one of the most active players there, where it was largely responsible for crafting the WiMAX RCT (Radio Conformance Test) docs. The company also lays claim to being the first to provide standards-compliant IEEE-802.16 physical-layer test gear for both fixed and Mobile WiMAX, including WiBro.

Proven Bits
Notably, the N8300A Wireless Networking Test Set expands the use of the company's existing--and proven -- vector signal analysis (VSA) and vector signal generator (VSG) hardware. What makes this Mobile WiMAX product so usable is its one-button measurement and modulation analysis for complex OFDMA signals. I really like the unit’s small size, ease of navigation, and generally clean user interface.

On the RF side, Agilent’s hardware is capable of handling signals upwards from 75-MHz, with extensions that will eventually take the instrument through to 4.8-GHz. With an IF bandwidth that's variable to 40-MHz, the system's VSA section is a 14-bit configuration that uses a 100-MHz digital down-conversion scheme. The result is sampling resolution of 10-ns. That's backed with an acquisition buffer that can store 5-ms of signal. The front-end can also withstand better than 300-mW of RF, too, which should help prevent inadvertent overload disasters.

For its part, the system's stable and clean signal generator hardware, spanning 250-kHz out to 6-GHz, samples at rates to 126-Msample/s, and has a 100-MHz bandwidth spec. Effectively, the VSG DAC (digital-to-analog converter) dishes up 16 bits of resolution. That lets you enjoy an output amplitude resolution of 0.02 dB.

Software Makes it Play
The associated N6301A Measurement Application software is what really makes this hardware play. The package is responsible for the in-depth analyses of IEEE-802.16e-2005 modulation. Using it you can check for spectral flatness, error vector magnitude (EVM), and channel power. It also lets you check IQ (in-phase and quadrature) offsets and frequency errors, as well as symbol clock errors.

Significantly, you can also look at CCDF power statistics (Complementary Cumulative Distribution Function). Measuring CCDF can give you important information about Mobile WiMAX signals, such as peak-to-average power. One good CCDF curve can show how much time a signal spends at or above a given power level, with power shown in decibels relative to average power.

CCDF curves can also help confirm whether a component performs as specified. For example, in an RF power amplifier (PA), you might compare the CCDF curve of a signal at the input and output of the PA.

If your design is good, the curves should coincide. If the PA were to excessively compress the signal, however, the peak-to-average ratio of the signal would be lower at the PA output, with a decreased CCDF curve. If that were to occur, you'd have to increase the range of the amplifier to account for power peaks, or you could lower the average power of the signal in order to match the limitations of the PA. Making CCDF measurements at several points in a system can help you verify performance of individual blocks and components. Learn more about CCDF here.

In addition to CCDF metrics, Agilent's parametric test set and software can help you ascertain an RF system's spectral mask, measure power-vs-time, and observe IQ waveforms to determine average power. CW power measurements can also be determined, to within ±0.5 dB (CW), over an amplitude range from +23 dBm down to a tenth of a nanowatt (-70 dBm).

Keep in mind that Agilent Technologies says its product will be available in October; however, to date the company has released only a preliminary datasheet for the hardware and software. Nonetheless, the initial specs look impressive. RF-oriented test-and-measurement companies like Rohde & Schwarz and Anritsu and others are also offering their own versions of WiMAX physical-layer analysis tools, but the Agilent N8300A/N6301A looks like it will shape up as a competitor worthy of your scrutiny.

Agilent says the N8300A Wireless Networking Test Set, with associated N6301A 802.16 OFDMA Measurement Application software, will be available in October 2007. Base pricing for the N8300A Wireless Networking Test Set is $57,750 (includes the Agilent N8300A-505 4.8 GHz Wireless Networking Test Set and N6301A-1FP software license).