Analog Devices EVAL-AD5933EBZ User Manual page 8

UG-364
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To automatically calculate the gain factor(s) for the
subsequent sweep, click Calculate Gain Factor. The
evaluation software evaluates either a single midpoint
frequency gain factor or multipoint frequency gain factors,
that is, a gain factor for each point in the programmed sweep
(see 4 in Figure 12). The midpoint gain factor is determined
at the midpoint of the programmed sweep, and the multipoint
gain factors are determined at each point in the programmed
frequency sweep.
When either the midpoint gain factor or the multipoint gain
factors are calculated, a message appears on the evaluation
board software front panel, as shown in Figure 13. The gain
factor(s) returned to the evaluation software are subsequently
used for the sweep across the impedance under test.
Figure 13. Confirmation of a Midpoint Calculation or
a Multipoint Gain Factors Calculation
After the system interface software calculates the gain factor(s)
for the programmed sweep parameters, the results are shown
in the Calculated Gain Factor box.
Note that should any of the system gain settings (for example,
change in output excitation range or PGA gain) change after
the system is calibrated (that is, gain factor(s) are calculated),
it is necessary to recalculate the gain factor(s) to subsequently
measure accurate impedance results. The gain factor(s)
calculated in the software are not programmed into the
AD5933 RAM and are only valid when the evaluation
software program is open and running. The gain factor(s)
are not retained in the evaluation software when the software
program is closed.
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Click Start Sweep (see 5 in Figure 12) to begin the sweep.
Once the evaluation software completes the sweep, it
automatically returns both a plot of the impedance vs.
frequency and phase vs. frequency for the impedance
under test (see Figure 12).The progress of the sweep is
outlined with a progress bar, as shown in Figure 14.
Figure 14. Sweep Progress Bar (Blue)
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Click Measure in the Internal Temperature section of the
evaluation board software front panel to take a reading
from the on-board temperature sensor. This returns the
13-bit temperature of the device. See
for more information on the temperature sensor.
•
Click Download Impedance Data to download the frequency
sweep data (that is, frequency, impedance phase, real,
imaginary, and magnitude data) from the DFT of the sweep
(see 5 in Figure 12). The common dialog front panel is
presented as shown in Figure 15. Choose a file name in a
directory of choice and click Save (see Figure 15). This
saves the sweep data to a comma separated variable file
(.CSV) located in the chosen directory.
The contents of this file can be accessed by using Notepad
or Microsoft Excel to plot the data. Each file contains a single
column of data. The format of the downloaded data is shown
in Figure 16.
Figure 16. Opening the Sweep Data in Excel
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Evaluation Board User Guide
AD5933
1. CHOOSE
DIRECTORY
2. CHOOSE
FILE NAME
Figure 15. Saving the Sweep Data
data sheet
3. SAVE THE FILE