CDB5471 Datasheet, PDF (19/26 Pages) Cirrus Logic – Evaluation Board and Software

CDB5471
Figure 7. Configuration Window
3.2.5.3. FFT Window
This box allows the user to select the type of win-
dowing algorithm for FFT processing. Windowing
algorithms include the Blackman, Black-Harris,
Hanning, 5-term Hodie, and 7-term Hodie. The 5-
term Hodie and 7-term Hodie are windowing algo-
rithms developed at Cirrus Logic.
3.2.5.4. Histogram Bin Width
This box allows for a variable “bin width” when
plotting histograms of the collected data. Each ver-
tical bar in the histogram plot will contain the num-
ber of output codes contained in this box.
Increasing this number may allow the user to view
histograms with larger input ranges.
3.2.5.5. Samples to Discard
This number represents the number of CS5471
sample periods that will be ignored before the soft-
ware starts to collect samples (when the user press-
es on the Collect Button). After the software has
skipped over this many data samples, the software
will then begin to save samples from the device (for
all six channels). The number of samples that are
actually saved is equal to the number specified in
the Number of Samples box.
3.2.5.6. Ready Button
After the user has adjusted the parameters in the
Config Window to the desired settings, the user
must click on the READY button to close the Con-
fig Window and return to the Data Collection Win-
dow.
3.2.6 Analyzing Data
The evaluation software provides three types of
analysis tests - Time Domain, Frequency Domain,
and Histogram. The Time Domain analysis pro-
cesses acquired conversions to produce a plot of
Output Code versus Conversion Sample Number.
The Frequency Domain analysis processes ac-
quired conversions to produce a magnitude versus
frequency plot using the Fast-Fourier transform
(results up to Fs/2 are calculated and displayed).
The Histogram analysis test processes acquired
conversions to produce a histogram plot. Statistical
noise calculated are also calculated and displayed.
3.2.7 Time Domain Information
The following controls and indicators are associat-
ed with the Time Domain Analysis. Time domain
data can be plotted in the Data Collection Window
by setting the Time Domain / FFT / Histogram se-
lector to “Time Domain.”
3.2.7.1. Count
Displays current x-position of the cursor on the
time domain display.
3.2.7.2. Magnitude
Displays current y-value of the cursor on the time
domain display.
3.2.7.3. Maximum
Indicator for the maximum value of the collected
data set.
DS480DB1
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