REV. 0
EVAL-AD9874EB
–6–
The bottom right corner of the control panel (next to the ADI
logo) contains several buttons that are used to invoke various
actions as described below in descending order. Positioning the
pointer over the particular button followed by a left mouse click
invokes a particular action.
Run Self-Tuning Macro
—Clicking this button initiates a series
of commands detailed in the HELP menu that automatically
tunes the AD9874’s
-
ADC. Note, tuning is required upon
powering the AD9874 once the CLK frequency has stabilized.
Tuning is also required if the CLK frequency is varied.
National Instruments Data Acquisition Device Number
—
One should ensure that the number entered in the box corre-
sponds to the number used when installing the NIDAQ NI 6533
card software.
Observe Digitized, Complex Output Signal
—Once the
AD9874’s SPI registers have been properly configured (and its
-
ADC tuned), clicking this button will open another display
showing the complex I/Q output data in both the time and fre-
quency domain.
Observe Undecimated Modulator Output
—Once the
AD9874’s SPI registers have been properly configured (and its
-
ADC tuned), clicking this button opens another display in
which the spectrum of the undecimated
-
ADC can be observed.
Write
—Clicking this button causes all of the AD9874 SPI
registers to be updated with the values programmed on the screen.
Note, an automatic readback of the SPI registers occurs after
the write command and the results are shown on the bottom of
the control panel display.
Reset
—Clicking this button “resets” the AD9874 to its default
values as described in Table I of the AD9874 data sheet. Note,
the default values will also appear on the bottom of the control
panel display.
Done
—Clicking this button closes the AD9874_eval application.
Read
—Clicking this button reads back the contents of the
AD9874’s SPI registers and displays the values to the left of the
button.
Digitized, Complex Output Signal Display Description
Figure 4 shows the display that will appear after clicking on the
Observe Digitized, Complex Output Signal button. The displays
show the Complex FFT of the I and Q data (normalized to its
output data rate) as well as a time domain representation of the
I/Q waveform and its constellation. The AD9874’s attenuation
setting, signal strength, and reset fields can also be observed
graphically by changing the Embedded AGC Data_I/Q Constel-
lation switch to the appropriate position (assuming the AD9874’s
SSI is configured properly). Note, upon entering this display,
the control panel is rendered inactive while the display window
remains active.
The horizontal and vertical axes of the displays can be modified
by the following procedure: position cursor over the min (or max)
axis setting, left click mouse, and type in new axis setting. Indi-
vidual SPI registers can be updated by entering the designated
register number and value in the boxes located in the display’s
bottom left corner followed by a left click on the WRITE button.
The current status of the SPI registers can be observed in the
lower portion of the display window.
FFT WINDOW, BW AND # OF AVERAGES
PRINT PANEL
RETURN TO CONTROL DISPLAY
I/Q DATA DISPLAY
CONSTELLATION
DISPLAY
SELECT AGC DATA
OR AGC CONSTELLATION
SIGNAL
POWER
IN-BAND
NOISE POWER
SINGLE REGISTER SPI WRITE
SPI REGISTER CONTENT
COMPLEX FFT
Figure 4. Complex Output Signal Display with I/Q Constellation
