Signal generator enhanced by Rhode & Schwarz for testing envelope tracking power amplifiers
MUNICH, 22 Oct. 2013. Rohde & Schwarz in Munich is introducing an enhanced version of its R&S SMW200A high-end vector signal generator to enable quick and easy testing of envelope tracking power amplifiers for smartphones, base stations and tactical radios.
The test & measurement enhancement involves adding the R&S SMW K540 option for envelope tracking. Because of the specific power distribution of RF signals with modern communications standards such as LTE and WCDMA, power amplifiers generally exhibit poor efficiency since spare capacity has to be reserved for high crest factors.
With envelope tracking, the amplifier supply voltage is controlled such that it tracks the envelope of the RF signal. As a result, the amplifier always operates in a range close to its instantaneous maximum output power, considerably boosting amplifier efficiency. Using shaping functions, the amplifier can be optimized for linearity or efficiency.
The Rohde & Schwarz test and measurement device helps chipset manufacturers with a solution that generates fully synchronous RF and envelope waveforms in one instrument. Users can delay the RF waveform and the envelope waveform relative to each other by ±500 nanoseconds with 1-picosecond resolution.
Due to its outstanding performance characteristics, the R&S SMW200A delivers a low-noise envelope signal at the analog baseband outputs. The signal generator calculates the envelope waveform from the baseband signals in real time, so that all communications standards supported by the R&S SMW200A as well as custom waveforms can be used. A large selection of flexible shaping functions allows users to optimize the envelope in real time.
The envelope tracking parameters can be configured on the generator's straightforward graphical user interface. Automatic envelope voltage adaptation is available to speed up setup and testing time since the main parameters such as VCC voltage range, PAin range, DC modulator gain, DC offset and power offset only need to be entered once. Automatic recalculation of the envelope based on the power amplifier input level makes it possible to perform power sweeps over the amplifier's entire input range.
For more information contact Rohde & Schwarz online at www.rohde-schwarz.com.
John Keller | Editor
John Keller is editor-in-chief of Military & Aerospace Electronics magazine, which provides extensive coverage and analysis of enabling electronic and optoelectronic technologies in military, space, and commercial aviation applications. A member of the Military & Aerospace Electronics staff since the magazine's founding in 1989, Mr. Keller took over as chief editor in 1995.
