VT DSO-2A20 Manual Rev. 1.1
Virtins Technology
Processing], tick “Compensation1” and select the frequency compensation file saved
previously.
(3)
The streaming mode of the signal generator provides more functions (e.g. pink noise,
multitones) but consumes more computing power of the computer. DDS mode is thus
recommended if possible.
(4)
Some VT DSOs such as VT DSO-2810R and VT DSO-2820R are not equipped with a
built-in signal generator. You can use the computer sound card as the DAC device for the
signal generator instead. The probe calibration signal output is also able to generate MLS
signal. To configure it, go to [Setting]>[DAC Device], enable “Probe CAL” and select
“MLS”, please note that the frequency value beside “MLS” refers to the sampling
frequency rather than the signal frequency of the MLS signal.
1.9.2 Distortion, Noise Level, and Crosstalk Measurements
VT DSOs can be used to measure the distortion, noise level and crosstalk of a DUT whose
respective parameter is substantially inferior to the VT DSO used. Please refer to Multi-
Instrument software manual for a detailed description of these parameter measurements.
The measurement of THD, THD+N, SINAD, SNR, Noise Level, ENOB, Crosstalk, SFDR
requires a pure sine wave excitation while IMD measurement requires multitone excitation.
To avoid spectral leakage, which is critical in these tests, Kaiser 6 Window is recommended
and FFT size of the spectrum analyzer should be equal to or less than the Record Length of
the oscilloscope. Device Test Plan is required for automated test at multiple frequency points.
Note:
(1)
Unlike the magnitude frequency response measurement, the distortion, noise level and
crosstalk of the VT DSO itself cannot be compensated. Thus the setup can only be used
to test those DUTs that have a substantially inferior performance in the respective aspects
to the setup itself. Please refer to the hardware specifications of the VT DSO for
information.
(2)
The distortion, noise level and crosstalk of the setup itself can be measured by looping
the output of the signal generator back to the input of the oscilloscope. You may need to
adjust the amplitude of the test tone, voltage range of the oscilloscope, etc. to optimize
the settings.
1.9.3 Measurement of Derived Quantities
Multi-Instrument comes with nearly 200 pre-defined quantities called Derived Data Points
which are derived from the raw DAQ data, such as RMS values, Mean values, Peak
Frequency, etc. You can also define your own set of derived quantities using mathematical
expressions. This requires Multi-Instrument Pro. If you are measuring a physical quantity
other than voltage, you can enter the sensor sensitivity via [Setting]>[Calibration]>
“Sensor”> “Sensitivity” and “Unit”.
1.9.4 Some Pre-configured Measurement Settings
The pre-configured panel setting files for VT DSOs are stored in the directory: psf\VTDSO.
You may use them directly in your tests, or use them as templates to configure your own test
settings. You can load these panel setting files via [Setting]>[Load Panel Setting].
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