A Comprehensive Baseband Generator and Channel Emulator

Engineers designing, integrating and verifying receiver signal processing components and devices today face a critical challenge. They must keep pace with the rapid design changes imposed by their industry while dealing with the ever-increasing pressure to be first-to-market. Unfortunately, evolving and unclear standards complicate this challenge, leading to design uncertainty and making it more difficult for engineers to meet their schedules. Receiver signal processing test must be performed, but testing to the standard is not enough. Corner cases must also be tested and that testing must take place early in the development cycle, a process that requires either broad or no limits on test parameters. Without such testing, devices can fail under real-world conditions, causing significant rework downstream.

Addressing these challenges is the main goal of the Agilent N5106A PXB baseband generator and channel emulator (see Figure 1). As well suited for engineers working on product development as it is for those conducting advanced research, the PXB can keep pace with rapid design changes and evolving standards by testing receiver signal processing to standards and beyond. It is the only instrument that combines up to 12 DSP blocksósoftware-defined functional blocksóto construct over 20 calibrated configurations for multi-format baseband generation, real-time fading and signal capture (up to 4x2 MIMO) in a single box. These configurations, along with external instrument connections, can be redefined in seconds using the instrument user interface.

Figure 1 Agilent N5106A PXB baseband generator and channel emulator).

The Windows-based PXB offers up to 120 MHz modulation bandwidth and 512 MSa playback memory, making it ideal for playing back long test scenarios to better approximate real-world signals. It supports standard-based channel models with up to 120 MHz fading bandwidth or 24 paths per fading channel. Additionally, RF and digital I/Q signals can be captured from the engineerís device to the PXB, up to 512 MSa. Captured signals can be monitored using the Agilent 89600 Vector Signal Analysis (VSA) software and post-processed with the engineerís simulator or MATLAB®. Such capabilities enable the PXB to address a number of the issues that complicate receiver signal processing test, including design uncertainty, the time, cost and complexity of system setup and calibration, and rapidly evolving standards.

Design Uncertainty

By letting the engineer customize test cases and validate designs under real-world conditions with the broadest range of test parameters, the PXB effectively tackles the design uncertainty associated with evolving and unclear standards. Fully parameterized signals can be created for established and evolving standards (e.g., LTE, HSPA, W-CDMA, GSM/EDGE, TD-SCDMA, Mobile WiMAX^TM, WLAN, digital video and GPS) using Agilent Signal Studio software running on the PXB. Agilentís SystemVue software can be used for baseband development or to play back customized MATLAB waveforms. The PXB also allows the engineer to model the signal-propagation environment with fully parameterized, real-time channel emulation. The engineer can use pre-defined standards-based channel models, modify them or configure their own using the PXBís custom correlation table and antenna setup menu.

Time, Cost and Complexity of System Setup and Calibration

Testing receiver signal processing in multi-format devices is an expensive and time-consuming proposition. To stay on schedule, engineers need simple ways to connect and calibrate their equipment and generate independent, calibrated signals. With less instrumentation to manageójust one box is needed for multi-format, multi-channel baseband signal processing including baseband generation, real-time fading and signal captureóthe PXB dramatically simplifies test setup and eliminates the time-consuming work of combining cables, splitters and power meters to connect and calibrate instruments. Additionally, signal routing, summing, sync and calibration are all managed seamlessly inside the PXB. Such capabilities significantly reduce the time, cost and complexity associated with system setup and calibration.

Rapidly Evolving Standards

Testing receiver signal processing today and in the future requires a toolset that can adapt as standards evolve. To get the greatest value from an investment, the instrument used should therefore support multiple functions, future technologies, frequent use and easy upgrades. With the PXB, engineers can leverage one multipurpose diagnostic toolset across the entire R&D lifecycleófrom design, integration and verification to pre-conformanceóto perform numerous combinations of baseband generation, real-time fading and signal capture (see Figure 2). By providing multiple functions, license-key upgrades and easy on-site upgrades with no calibration required, and performance that can handle future technologies, the PXB also ensures that the userís investment returns ongoing value.

Conclusion
Testing receiver signal processing in todayís highly-dynamic communications industry can be a challenging and costly proposition. With its ability to minimize design uncertainty, reduce the time, cost and complexity of system setup and calibration, and maximize the userís investment through higher instrument utilization and easy upgrades, the PXB is the ideal solution to this dilemma. Moreover, its flexibility to test beyond standard requirements and to enable numerous combinations of baseband generation, real-time fading and signal capture ensures that engineersóboth today and in the futureóhave the tools they need to get to market on schedule while staying ahead of the competition.

Agilent Technologies Inc.,
Santa Clara, CA
(800) 829-4444,
www.agilent.com/find/PXB.
RS No. 302