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8.3
Program the CDCM7005
8.4
Program the TRF3761
8.5
DAC5687 Program
8.6
Carrier Suppression
Basic Test Procedure
Use the Default Settings on the CDCM7005 GUI (See
). This generates a 491.52-MHz clock.
•
Hit the GUI Send button
•
Verify that LEDs D12, D13, and D14 are illuminated
Use the Default Settings in the TRF3761 GUI (See
). This places a carrier at 2.14 GHz
•
Hit the GUI send button.
•
Verify the LED D15 is illuminated. This indicates that a locked LO is present.
•
Monitor RF output from the spectrum analyzer
•
Verify a single frequency tone at the default 2.14 GHz.
There may be side tones created by the default complex output of the DAC5687.
Table 6. Frequency Designations
VCO BAND
UMTS
GSM900
PCS
DCS1800
Midband (MHz)
2140
950
1960
1850
Low (MHz)
2110
935
1930
1805
High (MHz)
2170
960
1990
1880
•
The DAC PLL mode is disabled as per the default jumper settings on J31. See section 6.
•
Verify DACA and DACB Coarse Gain is set to 15
•
Ensure DAC Offsets and DAC fine gain for both A and B are set to 0
•
Set the spectrum analyzer as follows:
–
Center Freq: 2.14 GHz
–
RBW: 30 kHz, VBW: 300 kHz
–
Span: 491.52 MHz
–
Attn: 5 dB
–
Ref Level: 10 dBm
The carrier suppression can be tuned for better performance by adjusting the dc-offset controls on the
DAC5687. The default DAC GUI is shown below with the NCO mixer turned on to output a 61.44-MHz
tone. The output spectrum is illustrated in
.
24
TSW3003 Demonstration Kit
SLWU029D – October 2006 – Revised August 2007