EVAL-AD9834SDZ Analog Devices Inc, EVAL-AD9834SDZ Datasheet - Page 15

• 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

THEORY OF OPERATION
Sine waves are typically thought of in terms of their magnitude
form a(t) = sin (ωt). However, these are nonlinear and not easy
to generate except through piecewise construction. On the
other hand, the angular information is linear in nature, that is,
the phase angle rotates through a fixed angle for each unit of
time. The angular rate depends on the frequency of the signal
by the traditional rate of ω = 2π f .
+1
–1
2p
0
0
Figure 27. Sine Wave
2π
2π
MAGNITUDE
PHASE
4π
4π
6π
6π
Rev. C | Page 15 of 36
Knowing that the phase of a sine wave is linear and given a
reference interval (clock period), the phase rotation for that
period can be determined.
Solving for ω,
Solving for f and substituting the reference clock frequency for
the reference period (1/ f
The AD9834 builds the output based on this simple equation. A
simple DDS chip can implement this equation with three major
subcircuits: numerically controlled oscillator + phase modulator,
SIN ROM, and digital-to-analog converter (DAC). Each of these
subcircuits is discussed in the Circuit Description section.
Δ Phase = ω Δ t
ω = Δ Phase /Δ t = 2π f
f = Δ Phase × f
MCLK
/ 2π
MCLK
= Δ t ),
AD9834