New R&S SMW200A Digital Predistortion Option Shortens Test Time
and Simplifies Evaluation
of Envelope Tracking Amplifiers
Rohde & Schwarz has integrated real-time digital
its R&S SMW200A high-end vector signal
generator. Predistortion can extend
the operating range of
amplifiers but determining the right correction factors
has always been a time-consuming process.
Munich, February 13, 2014 — The new
R&S SMW-K541 digital predistortion option from Rohde & Schwarz allows users to import
predistortion coefficient tables directly into the R&S SMW200A. The signal generator uses
these delta values to adjust the baseband signal in real-time. The option greatly reduces test
times since predistorted waveforms no longer have to be tediously recalculated and imported
into the generator.
Amplifiers are most efficient when they operate near their maximum
output power, which occurs in the nonlinear range. Although more power efficient, this results
in distortions at the amplifier output, which considerably diminishes the amplifier's RF performance.
Developers, especially developers of envelope tracking power amplifiers for smartphones, base
stations and tactical radios, use digital predistortion to counteract this problem. In envelope
tracking, the supply voltage tracks the envelope of the RF signal. Envelope tracking can optimize
efficiency, but is a valid design approach only when predistortion is used to compensate for
The R&S SMW-K541 digital predistortion option allows users to
import an AM/AM or AM/PM table with correction factors directly into the R&S SMW200A.
The R&S SMW200A uses the table values to automatically calculate in real-time an amplitude
and phase offset for each I/Q sample. The original waveform file remains unchanged. Conventional
solutions require users to import a new, predistorted waveform file into the signal generator
each time the level changes.
Developers can use the digital predistortion option on all
communications standards supported by the R&S SMW200A as well as on their own custom waveforms.
For envelope tracking tests with predistortion, the digital predistortion option can be configured
and seamlessly combined with the R&S SMW-K540 envelope tracking option so that the envelope
signal can be generated either from an undistorted or predistorted signal.
The new R&S
SMW-K541 digital predistortion option for the R&S SMW200A is now available from Rohde &
Schwarz. The test solution will be presented at the Mobile World Congress 2014 in Barcelona
in hall 6, booth C40.
Rohde & Schwarz
The Rohde &
Schwarz electronics group is a leading supplier of solutions in the fields of test and measurement,
broadcasting, secure communications, and radiomonitoring and radiolocation. Founded 80 years
ago, this independent global company has an extensive sales network and is present in more than
70 countries. It has around 9300 employees and achieved a net revenue of EUR 1.9 billion (USD
2.5 billion) in fiscal year 2012/2013 (July 2012 through June 2013). The company is headquartered
in Munich, Germany.
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February 14, 2014