ad80164absvz Analog Devices, Inc., ad80164absvz Datasheet - Page 31

• Manufacturer Part Number: ad80164absvz
• Description: Dual, 12-/14-/16-bit,1 Gsps Digital-to-analog Converters
• Manufacturer: Analog Devices, Inc.

INTERPOLATION FILTER ARCHITECTURE
The AD9776A/AD9778A/AD9779A can provide up to 8× inter-
polation, or the interpolation filters can be entirely disabled. It
is important to note that the input signal should be backed off
by approximately 0.01 dB from full scale to avoid overflowing
the interpolation filters. The coefficients of the low-pass filters
and the inverse sinc filter are given in Table 14, Table 15, Table 16,
and Table 17. Spectral plots for the filter responses are shown in
Figure 57, Figure 58, and Figure 59.
Table 14. Half-Band Filter 1
Lower Coefficient
H(1)
H(2)
H(3)
H(4)
H(5)
H(6)
H(7)
H(8)
H(9)
H(10)
H(11)
H(12)
H(13)
H(14)
H(15)
H(16)
H(17)
H(18)
H(19)
H(20)
H(21)
H(22)
H(23)
H(24)
H(25)
H(26)
H(27)
H(28)
Upper Coefficient
H(55)
H(54)
H(53)
H(52)
H(51)
H(50)
H(49)
H(48)
H(47)
H(46)
H(45)
H(44)
H(43)
H(42)
H(41)
H(40)
H(39)
H(38)
H(37)
H(36)
H(35)
H(34)
H(33)
H(32)
H(31)
H(30)
H(29)
Integer Value
−4
0
+13
0
−34
0
+72
0
−138
0
+245
0
−408
0
+650
0
−1003
0
+1521
0
−2315
0
+3671
0
−6642
0
+20,755
+32,768
Rev. 0 Page 31 of 68
Table 15. Half-Band Filter 2
Lower Coefficient
H(1)
H(2)
H(3)
H(4)
H(5)
H(6)
H(7)
H(8)
H(9)
H(10)
H(11)
H(12)
Table 16. Half-Band Filter 3
Lower Coefficient
H(1)
H(2)
H(3)
H(4)
H(5)
H(6)
H(7)
H(8)
Table 17. Inverse Sinc Filter
Lower Coefficient
H(1)
H(2)
H(3)
H(4)
H(5)
Figure 57. 2× Interpolation, Low-Pass Response to ±4× Input Data Rate
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
0
–4
–3
(Dotted Lines Indicate 1 dB Roll-Off)
AD9776A/AD9778A/AD9779A
–2
Upper Coefficient
H(15)
H(14)
H(13)
H(12)
H(11)
H(10)
H(9)
Upper Coefficient
H(9)
H(8)
H(7)
H(6)
Upper Coefficient
H(23)
H(22)
H(21)
H(20)
H(19)
H(18)
H(17)
H(16)
H(15)
H(14)
H(13)
f
OUT
–1
(× Input Data Rate)
0
1
Integer Value
−39
0
+273
0
−1102
0
+4964
+8192
Integer Value
+2
−4
+10
−35
+401
2
Integer Value
−2
0
+17
0
−75
0
+238
0
−660
0
+2530
+4096
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