Nujira aims to push the envelope with advanced software tool for PA characterization and visualization

June 15, 2012 // Paul Buckley

Nujira Ltd has released an advanced measurement and data visualization tool for characterizing RF power amplifiers (PAs) in ET mode.

ET Surface Explorer is a software upgrade to Nujira’s existing NCT-T9102 RF PA characterization system. It accelerates PA characterization, provides PA and product designers greater insight into the performance of ET PAs, and enables them to maximize the linearity, efficiency and output power benefits of operating PAs in ET mode.

ET Surface Explorer’s advanced workflow provides a massive productivity boost, replacing thousands of complex, repetitive and time-consuming lab measurements with a single measurement pass, which typically takes less than two minutes to capture and process.

ET Surface Explorer lets designers visualize how PAs behave under live ET supply modulation conditions, unlocking the optimum performance and efficiency characteristics of a given PA. Postprocessing and offline analysis tools create 3D surfaces of gain, phase and efficiency, to give designers far greater insight into ET PA performance.  The tool can also automatically generate, model and export a wide variety of shaping tables, including ISOGAIN or Maximum Efficiency.

ET Surface Explorer’s offline analysis and modeling tools allow the designer to rapidly predict and compare application performance from the comfort of their desk, without requiring multiple test iterations in the lab. The user simply loads an input waveform from disk, specifies the RF power level and selects a shaping table or DC supply voltage.  ET Surface Explorer then uses the captured PA surface model to accurately predict adjacent channel leakage ratio (ACLR), efficiency, AM/AM and AM/PM distortion, power dissipation and other parameters in a matter of seconds.  Selected scenarios can then be re-verified in hardware, and compared against the predictions of the model.

The accurate characterization and visualization capabilities enabled by Surface Explorer not only allow designers to optimize and compare PA performance, but also to quantify other useful ET system benefits such as increased output power, broadband operation, improved performance into mismatched loads and insensitivity to temperature variations. At each operating point of interest, a single ET surface can be captured in a few seconds.  Each surface captured replaces up to 3,000 discrete measurements, saving time and building a powerful database of PA performance, which can be analyzed and mined offline.

Tim Haynes, CEO of Nujira said: “The release of ET Surface Explorer shows our continued commitment to supporting RF designers by making the adoption of Envelope Tracking technology as painless as possible. Our NCT-T9102 PA characterization system was already far ahead of the competition in terms of accurately measuring and analyzing the performance of ET PAs, and ET Surface Explorer gives designers another powerful tool to simply and intuitively optimize PA performance.  Smartphone designers and modem chipset developers can also benefit from ET Surface Explorer’s high productivity workflow, allowing them to compare and assess ET PA device performance in a few hours, rather than days.”

Accurately measuring the efficiency of an Envelope Tracking PA under dynamic supply modulation is one of the most challenging tasks faced by developers of RF Power Amplifiers. It requires generation of precisely time-aligned envelope and RF signals; a high bandwidth, high current, low impedance power supply modulator; high bandwidth sensing of instantaneous current and voltage supplied to the PA; and measurement of the instantaneous RF power at input and output of the PA. All of this data must be captured at more than 100 million samples/second, and then correlated to calculate the instantaneous efficiency of the RF PA.

ET Surface Explorer, used in conjunction with Nujira’s Flexible Development System waveform generator, captures data across the entire ET RF power/supply voltage plane, and creates surfaces of gain, phase and efficiency.  Capture conditions are carefully designed to mimic true ET operation and provide accurate modeling of linearity and efficiency over a wide dynamic range.

Already available to alpha customers, Nujira’s ET Surface Explorer software is scheduled for production release in Q4 2012.

Visit Nujira at www.nujira.com

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December 15, 2011 | Texas instruments | 222901974

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