N7621B Datasheet, PDF (4/12 Pages) Keysight Technologies – Signal Studio for Multitone Distortion

Verify Subsystems or Satellite Transponder with NPR test
LAN/GPIB
Digitally synthesized NPR stimulus
PSG
PXA
Figure 2. Create specified wideband NPR signals with very sharp and deep notches.
Signal Studio for multi-tone enables users to easily generate an appropriate noise stimulus
for wideband components or subsystems such as satellite transponders. Signal Studio
creates several thousand closely spaced discrete frequencies that are level in amplitude
across the band of interest.
NPR test is ideal to characterize intermodulation distortion performance in an objective and
quantitative manner while simulating worst-case loading conditions. Traditional creation of
a wideband NPR signal required the use of a wideband noise generator with a notch filter.
While this test was effective for determining performance, it lacks repeatability and can be
very costly. Signal Studio for multitone and NPR does a much better job of creating these
signals at a lower cost than the analog approach.
The digital noise generation technique used by Signal Studio produces an ideal NPR test
stimulus which brings advantages to traditional approaches:
–– A calibrated flat amplitude accurate signal which can include noise statsitics for more
accurate crest factor test that is a great indication of the “stress factor” of the device
or device under test (DUT)
–– Sharp spectral shape definition unlike an analog approach gives a much more accurate
and repeatable measurement result
–– Very predictable and repeatable signal shape for consistent testing across devices
and projects
–– Proprietary algorithm can significantly improve notch depth and other distortion prod-
ucts to maximize capability of test equipment to give a significant improvement in NPR
measurement error
–– Calibrate measurement all the way to the device, correcting for both test equipment
and other elements in the test fixture
–– Works in conjunction with the highest performance hardware which provides very large
bandwidths with high dynamic range
With the ability to generate precise and repeatable stimulus for NPR measurements, the
digital method of determining NPR is in many ways superior to analog methods for evaluating
the effects of intermodulation distortion in amplifiers and other communications devices.
By simplifying the process of generating a digital test stimulus, Signal Studio for multitone
distortion makes evaluation of non-linear distortion characteristics faster and easier.
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