Texas Instruments ADS9224REVM-PDK, User Manual, Page: 18 / 34

Operation
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18 SBAU315A – July 2018 – Revised June 2019
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ADS9224REVM-PDK
Finally, the FFT tool includes windowing options that are required to mitigate the effects of noncoherent
sampling (a discussion that is beyond the scope of this document). The 7-Term Blackman Harris window
is the default option and has sufficient dynamic range to resolve the frequency components of up to a 24-
bit ADC. The
None option corresponds to not using a window (or using a rectangular window) and is not
recommended.
6.5 Histogram Tool
Noise degrades ADC resolution. The histogram tool can be used to estimate effective resolution . Effective
resolution 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 corresponding to a dc input is displayed on clicking the Capture button, as shown in
Figure 14 :
Figure 14. Histogram Analysis Tool