EVAL-AD7482CB Datasheet, PDF (9/20 Pages) Analog Devices – Evaluation Board for 3 MSPS, 12-Bit SAR ADC

MENU BAR
CONTROL
BUTTONS
DIGITAL
STORAGE
OSCILLOSCOPE
(DSO)
STATUS BOXES
EVAL-AD7482CB
FAST
FOURIER
TRANSFORM
(FFT)
Figure 4. AD7482 Main Dialog Box
SOFTWARE DESCRIPTION
The software that controls the EVAL-CONTROL BRD2 and
the evaluation board consists of three dialog boxes. The screen
shown in Figure 4 appears when the software is running. The
main function of this screen is to allow the user to read a prede-
termined number of samples from the evaluation board and
display them both in the time and frequency domain. The screen
can be divided into three sections.
The upper third of the screen contains the control buttons, the
menu bar, and various status windows. The control buttons
allow the user to take samples, reset the part, and quit the
program. The menu bar allows the user to enter the setup
menu, select which printer port to use to control the EVAL-
CONTROL BRD2, load and save data, and get information
about the software. The status windows indicate the setup of
the evaluation board/device, number of samples taken, and any
information or error messages generated.
The middle third of the screen is a digital storage oscilloscope
(DSO). When samples are uploaded from the EVAL-CONTROL
BRD2 they are displayed here. The samples can be displayed either
as integer values or as voltages (determined by the input range
of the device in question). Once samples have been displayed,
clicking at any point in the graph shows the sample number and
the value of the point directly beneath the cursor. Along the axis
of the graph are zoom handles. These allow the user to zoom
in and out to get a closer look at a particular sample if required.
When another set of samples is taken, the graph attempts to
display all values collected unless the Hold Zoom check box has
been selected. In this case, the graph keeps the same axis settings
as for the previous set of data samples. Additional check boxes
are provided to give the user control over the vertical and
horizontal grids and data points.
The lower third of the screen shows either a fast Fourier
transform (FFT) of the data or a histogram which displays the
number of occurrences of each particular code read back. The
FFT (default option) is typically used when the user is concerned
with examining an ADC’s performance in the frequency domain
while the histogram gives an indication of the ADC’s perform-
ance with DC signals. The option displayed can be toggled by
clicking the FFT Mode/Histogram Mode button in the top right
of the screen. Figure 5 shows how the main screen looks when
the Histogram option is selected.
Sample Button
When the user clicks Sample, the software instructs the EVAL-
CONTROL BRD2 to take the required number of samples at
the required frequency from the evaluation board. The AD7482
evaluation board runs up to 2.2 MSPS so the user can choose
any sampling frequency up to this rate as well as the number of
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