14 Feb 2012

Nujira RF Power Amplifier Characterisation System

Envelope tracking specialist, Nujira has launched a new handset RF power amplifier, PA characterisation system.

Full PA characterisation is a notoriously difficult item to achieve. Characterising the input and output power levels even under relatively static conditions is not always easy.

However modern handset PAs require continuously changing conditions to operate efficiently. The Nujira envelope tracking, ET, system that increases PA efficiency by a considerable degree makes characterisation even more difficult using standard test equipment.

In response to their own need, Nujira developed an in-house system, and this has been further developed as an item of test equipment for PA vendors, and other developers who need to measure the performance of their PAs, especially if they involve envelope tracking. It has been designated the NCT-T9102. The NCT-T9102 captures all the required data including efficiencies, phases power levels, and then feeds this into a computer for analysis by specially developed software.

Accurate efficiency measurements of a power amplifier using envelope tracking is a challenging task because under dynamic supply modulation conditions, all the parameters are changing. Measurements require a precisely time-aligned envelope and RF signals. This needs 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. To achieve full analysis, the data must be captured at a rate of more than 100 million samples/second. This is then correlated to calculate the instantaneous efficiency of the RF PA.

The NCT-T9102 is already in use by several major PA vendors and OEMs worldwide. It is being used to characterize existing PAs and also to develop future ET-optimized PA devices. It can be particularly useful in assessing the gains of envelope tracking by OEMs and platform chipset vendors.

Tim Haynes, CEO of Nujira commented: “Nujira is working with the world’s leading suppliers of RF Power Amplifiers to enable them to develop and bring to market high performance handset PAs which take full advantage of the system benefits offered by Envelope Tracking. Providing our partners with this dedicated test equipment is a critical step in our roadmap to enable an industry-wide ET ecosystem for PA vendors and handset OEMs.”

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