Nujira has launched Envelope Tracking (ET) Surface Explorer, a measurement and data visualisation 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 characterisation system. It accelerates PA characterisation, provides PA and product designers greater insight into the performance of ET PAs, and enables them to maximise the linearity, efficiency and output power benefits of operating PAs in ET mode.
ET Surface Explorer’s workflow provides a productivity boost, according to Nujira, replacing thousands of complex, repetitive and time-consuming lab measurements with a single measurement pass, which typically takes less than 2 minutes to capture and process.
ET Surface Explorer lets designers visualise 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 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 modelling 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 characterisation and visualisation capabilities enabled by Surface Explorer not only allow designers to optimise 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 analysed and mined offline.
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 modelling of linearity and efficiency over a wide dynamic range.