Circuit Note

CN-0243

Rev. 0 | Page 7 of 8

PC

I

Q

USB

+5V

GND

USB

USB ADAPTER

BOARD

DPG2

DIGITAL PATTERN

GENERATOR

EVAL-CN0243-EB1Z

EVALUATION BOARD

REFERENCE

FREQUENCY

GENERATOR

10MHz – 200MHz +3dBm

SPECTRUM

ANALYZER

POWER

SUPPLY

PLL REFERENCE

INPUT

RF OUTPUT

IQ DATA

DIGITAL

INTERFACE

Figure 13. Test Setup Functional Block Diagram

data rate should be equal to the DAC sample rate

(614.4 MSPS) in Figure 13 divided by the programmed

interpolation rate of the AD9122.

5. Note that as the various devices are activated and

programmed, the current will increase. At the end of this

exercise, the current should be between 1.4 A and 1.5 A,

depending on DAC sample rate.

6. Use the DPG2 software to create a waveform (single,

multi tone, or comms standard signals are available).

A digital back-off of −8 dB should be used initially to

optimize linearity of the DAC/ADRF6702 combination.

Complex signal generation should also be selected in the

DPG2 GUI. When the waveform is created, use the "load"

and "play" buttons in the GUI to load the digital pattern

into the DPG memory itself.

7. Start the ADRF6702 GUI. To begin with, the only options

in the ADRF6702 GUI which need to be selected are the

input reference frequency and LO output frequency. To

program these values, click the reference input frequency

or the LO output values in the top center of the

ADRF6702 GUI. Another window will appear which will

allow you to enter these values. Important: After entering

these values, the user must finish with a carriage return to

make sure that the values are entered into the GUI.

8. Programming the ADRF6702 is the last step in setting up

the EVAL-CN0243-EB1Z evaluation board. As an

example, if the DPG2 generates a series of tones (20 MHz

to 25 MHz with 1 MHz spacing) @ −8 dB back-off, and

the LO of the ADRF6702 is programmed to 1940 MHz,

the spectrum should look very similar to that shown in

Figure 14.

–20

–30

–40

–50

–60

–120

–110

–100

–90

–80

–70

CENTER 1.94GHz

10MHz/DIV

SPAN 100MHz

REF –20dBm

ATT 10dBm

RBW 10kHz

VBW 30kHz

SWT 15ms

MARKER 1 [T1]

–104.90dB

1.89005GHz

Figure 14. Spectrum of Complex Multitone Signal at LO Frequency of

1940 MHz at ADRF6702 RF Output, Desired Sideband Offset: +20 MHz,

Undesired Sideband Offset: −20 MHz