6.3.3 Histogram Analysis
The
Histogram Analysis
tool plots the histogram of the raw ADC conversion data for ADC1A, ADC1B, ADC3A,
and ADC3B. This tool is useful for studying the statistical summary of the data set, mainly by computing the
mean and standard deviation of the data from each channel. Noise degrades ADC resolution and the histogram
tool can estimate an effective resolution, which is an indicator of the number of bits of ADC resolution losses
resulting from noise generated by the various sources connected to the ADC when measuring a DC signal. The
cumulative effect of noise coupling to the ADC output from sources such as the input drive circuits, the reference
drive circuit, the ADC power supply, and the ADC is reflected in the standard deviation of the ADC output code
histogram that is obtained by performing multiple conversions of a DC input applied to a given channel.
The histogram bin width is calculated using Scott's Rule by default. This method minimizes the mean-squared
error in the bin approximation, assuming the data follows a Gaussian distribution. Alternatively, select
Custom
under the
Binning Rule
drop-down menu and enter the desired
Codes per Bin
setting in the field to the right.
Below the histogram plot is a
Measurements
summary table, which lists the
Minimum
,
Maximum
,
Sigma
,
Peak-
to-Peak
, and
Number of Bins
for each channel. The histogram x-axis and the table statistics can be displayed in
Codes
or
Voltage (V)
by toggling the radio buttons under the
Unit
section to the right of the table.
Initiate data capture by specifying the number of samples and clicking the
Capture
button at the bottom of the
Data Capture Configuration
panel.
shows an example data capture with all channels configured for an
internal input short. ADC1A and ADC1B are configured for Gain = 4, and ADC3A and ADC3B are configured for
Gain = 1.
Figure 6-7. Histogram Analysis Tool
ADS131B26Q1EVM-PDK Software Reference
22
ADS131B26Q1EVM-PDK Evaluation Module
SBAU413 – OCTOBER 2022
Copyright © 2022 Texas Instruments Incorporated
