AD9786 Analog Devices, AD9786 Datasheet - Page 36

• Manufacturer Part Number: AD9786
• Manufacturer: Analog Devices

Specifications of AD9786

• Resolution (bits): 16bit
• Dac Update Rate: 500MSPS
• Dac Settling Time: n/a
• Max Pos Supply (v): +3.5V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: Par

AD9786
Table 33. Dual-Channel Complex Modulation
MODDUAL
0
0
0
0
0
0
0
0
In dual-channel mode, the two channels can be modulated by
a complex signal, with either the real or imaginary modulation
result directed to the DAC. Assume initially, as in Figure 63,
that the complex modulating signal is defined for a positive
frequency only. This causes the output spectrum to be trans-
lated in frequency by the modulation factor only. No additional
sidebands are created as a result of the modulation process;
therefore, the bandwidth to the first image from the baseband
bandwidth is the same as the output of the interpolation filters.
Furthermore, pass bands do not overlap or touch. The sinc
shaping at the corners of the modulated signal band is tabulated
in Table 34. Figure 64, Figure 65, and Figure 66 show the effects
of complex modulation with varying interpolation rates.
CHANNEL
0
0
0
0
1
1
1
1
MOD[1]
0
0
1
1
0
0
1
1
FILTERED INTERPOLATION IMAGES
Figure 63. Complex Modulation
Rev. B | Page 36 of 56
f
S
/8 MODULATION
0
1
0
1
0
1
0
1
MOD[0]
Table 34. Complex Modulated Pass-Band Edges Sinc Shaping
(Lower/Upper)
Modulation
None
f
f
f
DAC
DAC
DAC
/2
/4
/8
NO NEGATIVE
SIDEBAND
Mode
Real output, no modulation
Real output, modulation by f
Real output, modulation f
Real output, modulation f
Image output, no modulation
Image output, modulation by f
Image output, modulation by f
Image output, modulation by f
None
0
–2.8241
–0.0701
–22.5378
–0.4680
–6.0630
–1.3723
–4.9592
×2
0
–0.6708
–1.1932
–9.1824
–0.0175
–3.3447
–0.1160
–1.7195
DAC
DAC
Interpolation
/4
/8
DAC
DAC
DAC
DAC
/2
/2
/4
/8
×4
0
–0.1657
–2.3248
–6.1190
–0.2921
–1.9096
–0.0044
–0.7866
×8
0
–0.0413
–3.0590
–4.9337
–0.5974
–1.3607
–0.0727
–0.4614