AD9954 Datasheet, PDF (35/36 Pages) Analog Devices – 400 MSPS 14-Bit, 1.8 V CMOS Direct Digital Synthesizer

SUGGESTED APPLICATION CIRCUITS
RF/IF INPUT
MODULATED/
DEMODULATED
SIGNAL
AD9954
LPF
REFCLK
Figure 29. Synchronized L.O. for Upconversion/Down Conversion
REF
SIGNAL
PHASE
COMPARATOR
LOOP
FILTER
FILTER
AD9954
VCO
TUNING
WORLD
Figure 30. Digitally Programmable Divide-by-N Function in PLL
AD9954
TUNING WORD
IOUT
LPF
AD9954 DDS
IOUT
LPF
AD9954
ON-CHIP
COMPARATOR
CMOS LEVEL CLOCK
Figure 31. Frequency Agile Clock Generator
FREQUENCY PHASE
TUNING
OFFSET
WORD
WORD 1
I/I-BAR
BASEBAND
REFCLK
SAW
CRYSTAL
IOUT
AD9954 DDS _IOUT
LPF
REFCLK
CRYSTAL OUT SYNC OUT
RF OUT
SYNC IN
AD9954 DDS ^IOUT
LPF
IOUT
REFCLK
FREQUENCY
TUNING
WORD
PHASE
OFFSET
WORD 2
Q/Q-BAR
BASEBAND
Figure 32. Two AD9954s Synchronized to Provide I and
Q Carriers with Independent Phase Offsets for Nulling
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