EVAL-ADAQ23875FMCZ
User Guide
UG-1896
Rev. 0 | Page 9 of 26
code transition. The deviation is measured from the middle of
each code to the true straight line.
In an ideal ADC, code transitions are 1 LSB apart. DNL is the
maximum deviation from this ideal value. DNL is often specified
in terms of resolution for which no missing codes are guaranteed.
To perform a linearity test, apply a sinusoidal signal with 0.5 dB
above full scale to the EVAL-ADAQ23875FMCZ board at the
VIN+ and VIN− Subminiature Version A (SMA) inputs. Set
the number of hits per code and adjust to the desired accuracy.
Using a large number of hits per code results in a significant
test time. Figure 16 and Figure 17 display captured data that
includes the ±INL and ±DNL positions.
Analysis Pane
The
General Settings
section allows the user to set up the
preferred configuration of the FFT analysis. This configuration
sets how many tones are analyzed and if the fundamental is set
manually.
The
Windowing
section allows the user to set up the preferred
windowing type to use in the FFT analysis and the number of
harmonic bins and fundamental bins that must be included in
the analysis.
The
Single Tone Analysis
and the
Two-Tone Analysis
sections
sets up the fundamental frequencies included in the FFT
analysis. When one frequency is analyzed, use the
Singe Tone
Analysis
section
.
When two frequencies are analyzed, use the
Two-Tone Analysis
section.
Results Pane
The
Signal
section displays the sample frequency, fundamental
frequency, and fundamental power.
The
Noise
section displays the signal-to-noise ratio (SNR) and
other noise performance results.
The
Distortion
section displays the harmonic content of the
sampled signal and dc power when viewing the FFT analysis.
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010
Figure 10. EVAL-ADAQ23875FMCZ
ACE
Software Main Window
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