AD9148 Analog Devices, AD9148 Datasheet - Page 53

• Manufacturer Part Number: AD9148
• Manufacturer: Analog Devices

Specifications of AD9148

• Resolution (bits): 16bit
• Dac Update Rate: 1GSPS
• Dac Settling Time: n/a
• Max Pos Supply (v): +3.47V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: LVDS,Par

Data Sheet
As shown in Figure 66 and Figure 67, the center frequency in
each mode is offset by ¼ of the input data rate (f
Mode 0 through Mode 3 do not modulate the input signal. Mode 4
through Mode 7 modulate the input signal by f
in Mode 0 and Mode 4, the I and Q paths operate independently,
and no mixing of the data between channels occurs. When
operating in the other six modes, mixing of the data between
the I and Q paths occurs; therefore, the data input to the filter
is assumed complex. Table 21 summarizes the HB2 modes.
Table 21. 4× Interpolation Filter Modes (Register 0x1C to
Register 0x1E)
Interpolation
Factor
4
4
4
4
4
4
4
4
Figure 68 shows the pass-band filter response for HB2. In most
applications, the usable bandwidth of the filter is limited by the
image suppression provided by the stop-band rejection and not
by the pass-band flatness. Table 22 shows the pass-band flatness
and stop-band rejection the HB2 filter supports at different
bandwidths.
–100
–20
–40
–60
–80
0
0
0.2
MODE 1
0.4
Figure 67. HB2, Odd Filter Modes
Pre-Mod
0
1
0
1
0
1
0
1
0.6
0.8
Filter Modes
MODE 3
HB1
0
1
2
3
0
1
2
3
(×
1.0
f
IN2
)
1.2
MODE 5
HB2
0
1
2
3
4
5
6
7
1.4
IN2
MODE 7
. When operating
1.6
HB3
Off
Off
Off
Off
Off
Off
Off
Off
IN2
) of the filter.
1.8
f
(f
0
f
f
3f
f
−3f
−f
−f
DAC
DAC
DAC
CENTER
2.0
DAC
DAC
DAC
DAC
/8
/4
/2
DAC
)
/8
/4
/8
Rev. B | Page 53 of 72
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Table 22. HB2 Pass-Band and Stop-Band Performance by
Bandwidth
Bandwidth (% of f
50
50.8
52.8
56.0
60
64.8
Half-Band Filter 3 (HB3)
HB3 has eight modes of operation that function the same as HB2.
The primary difference between HB2 and HB3 are the filter
bandwidths. Table 23 summarizes the filter modes for HB3.
Table 23. 8× Interpolation Filter Modes (Register 0x1C to
Register 0x1E)
Interpolation
Factor
8
8
8
8
8
8
8
8
–0.02
–0.04
–0.06
–0.08
–0.10
0.02
0
0
0.04
Figure 68. Pass-Band Detail of HB2
Pre-Mod
0
0
0
0
0
0
0
0
IN2
0.08
)
0.12
Filter Modes
Pass-Band
Flatness (dB)
0.001
0.0012
0.0028
0.0089
0.0287
0.1877
HB1
0
2
0
2
0
2
0
2
(×
0.16
f
IN2
)
0.20
HB2
0
2
4
6
0
2
4
6
0.24
HB3
0
1
2
3
4
5
6
7
Stop-Band
Rejection (dB)
85
80
70
60
50
40
0.28
AD9148
0.32
f
(f
0
f
f
3f
f
−3f
−f
−f
DAC
DAC
DAC
CENTER
DAC
DAC
DAC
DAC
/8
/4
/2
DAC
)
/8
/4
/8
/8