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Verification of High-Efficiency Power Amplifier Performance at Nujira

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Sean Lynch, Nujira

Verification of High-Efficiency Power Amplifier Performance at Nujira

This presentation describes the approaches and tools we have used to verify the operation of our modulator designs. We use MathWorks tools across the entire development life cycle of our products from research, through design, to verification and automated testing.

RF power amplifiers (PAs) ensure that the source radio frequency (RF) signal, such as a DVB, 3G, LTE, or 4G signals, is powerful enough for transmission. Because PAs use a fixed supply voltage, they draw maximum power whatever the amplitude of the signal, making them notoriously inefficient for amplitude modulated RF signals. Conventional PAs waste as much as 80% of the energy they consume as dissipated heat. The PAs in a cellular base station, for example, account for half the total power consumed.

Although envelope tracking was first described more than 60 years ago, it has not been applied commercially until recently, largely due to the difficulty of implementing a power supply modulator that meets the efficiency, bandwidth, and noise requirements of wideband signals such as multicarrier WCDMA, WiMAX, or DVB.

Nujira’s envelope tracking technology can double the efficiency of PAs and dramatically reduce power dissipation, which lowers energy bills and substantially reduces the amount of cooling required. It also enables higher device output power, allowing broadcasters to extend the range of existing broadcasting towers. Lastly, the wideband operation of Nujira’s technology enables broadcasters to use fewer PA designs to cover their target broadcast spectrum. For handset applications, the use of envelope tracking also improves PA linearity. This is achieved by dynamically modulating the amplifier’s supply voltage according to the RF signal passing through the device.

Nujira’s High Accuracy Tracking (HAT) technology, the first practical implementation of envelope tracking, is being used or evaluated for cellular infrastructure and terminals, broadcast transmitters, military communications, and other applications. It is featured in three product lines: Coolteq.L for mobile handsets, Coolteq.h for cellular base stations, and Coolteq.u for DVB transmitters.