EVAL-AD7276SDZ User Guide
UG-450
Rev. 0 | Page 17 of 20
GENERATING A HISTOGRAM OF THE ADC CODE
DISTRIBUTION
The Histogram tab can be used to perform ac testing or, more
commonly, dc testing. This tab shows the ADC code distribution of
the input and computes the mean and standard deviation, which
are displayed as Mean and Transition Noise, respectively, in the
Histogram Analysis area (labeled 1 in Figure 19).
Figure 19 shows the histogram with ac input for a 50 kHz sine
wave applied to the ADC input and the resulting calculations.
AC Input
To perform a histogram test of ac input,
1.
Apply a signal source to the selected analog input on the board.
2.
Click the Histogram tab from the main window.
3.
Click Sample.
Raw data is then captured and passed to the PC for statistical
computations, and various measured values are displayed in the
Histogram Analysis area.
DC Input
A histogram test of dc input can be performed with or without
an external source because the evaluation board has a buffered
V
REF
/2 source at the ADC input.
To perform a histogram test of dc input,
1.
If an external source is being used, apply a signal source to the
selected analog input. It may be required to filter the signal to
ensure that the dc source is noise-compatible with the ADC.
2.
Click the Histogram tab from the main window.
3.
Click Sample.
Raw data is then captured and passed to the PC for statistical
computations, and various measured values are displayed in the
Histogram Analysis area.
Figure 19. Histogram Tab
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