EVAL-AD9834SDZ Analog Devices Inc, EVAL-AD9834SDZ Datasheet - Page 23

• Manufacturer Part Number: EVAL-AD9834SDZ
• Description: Evaluation Board I.c.
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD9834SDZ

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
Because of the various output options available from the part,
the AD9834 can be configured to suit a wide variety of
applications.
One of the areas where the AD9834 is suitable is in modulation
applications. The part can be used to perform simple modulation
such as FSK. More complex modulation schemes such as GMSK
and QPSK can also be implemented using the AD9834.
In an FSK application, the two frequency registers of the
AD9834 are loaded with different values. One frequency
represents the space frequency, and the other represents the
mark frequency. The digital data stream is fed to the FSELECT
YES
YES
CHANGE FREQUENCY
V
OUT
CHANGE FSEL/
REGISTER?
FSELECT?
CONTROL
REGISTER
= V
WRITE
REFOUT
NO
× 18 × R
Figure 31. Flow Chart for Initialization and Operation
LOAD
YES
YES
YES
/R
SET
Rev. C | Page 23 of 36
× (1 + (SIN(2π(FREQREG × f
CHANGE FREQUENCY?
CHANGE DAC OUTPUT
SEE TIMING DIAGRAM
FROM SIN TO RAMP?
CHANGE OUTPUT AT
SIGN BIT OUT PIN?
CHANGE PHASE?
SEE FIGURE 33
SEE FIGURE 34
WAIT 8/9 MCLK
SELECT DATA
DAC OUTPUT
DATA WRITE
SOURCES
FIGURE 3
CYCLES
NO
NO
NO
NO
pin, causing the AD9834 to modulate the carrier frequency
between the two values.
The AD9834 has two phase registers, enabling the part to
perform PSK. With phase shift keying, the carrier frequency is
phase shifted, the phase being altered by an amount that is
related to the bit stream that is input to the modulator.
The AD9834 is also suitable for signal generator applications.
With the on-board comparator, the device can be used to
generate a square wave.
With its low current consumption, the part is suitable for
applications where it is used as a local oscillator.
MCLK
YES
× t/2
28
+ PHASEREG/2
CHANGE PHASE
CHANGE PSEL/
INITIALIZATION
SEE FIGURE 32
REGISTER?
PSELECT?
NO
YES
12
))))
YES
AD9834