EVAL-AD7902SDZ Datasheet, PDF (17/32 Pages) Analog Devices – On-board reference

EVAL-AD7902SDZ User Guide
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 DC Offset/Mean and Transition Noise, respectively,
in the Histogram Analysis area (located toward the bottom of
the window).
Figure 23 shows the histogram with ac input for a 1 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 sinusoidal signal with low distortion (better than
100 dB) to the evaluation board at the J6 or J14 input SMA
connector pair.
2. Click the Histogram tab from the main window.
3. Click Single Capture or Continuous Capture.
Raw data is then captured and passed to the PC for statistical
computations, and various measured values are displayed in the
Histogram Analysis area.
UG-608
DC Input
A histogram test of dc input can be performed with or without
an external source because the evaluation board has a buffered
VREF/2 source at the ADC input.
To perform a histogram test of dc input,
1. If an external source is being used, apply a sinusoidal signal
with low distortion (better than 100 dB) to the evaluation
board at the J6 or J14 input SMA connector pair. 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 Single Capture or Continuous Capture.
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 23. Histogram Tab
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