AD9148BPCZ AD [Analog Devices], AD9148BPCZ Datasheet - Page 53

• Manufacturer Part Number: AD9148BPCZ
• Description: Quad 16-Bit,1 GSPS, TxDAC+ Digital-to-Analog Converter
• Manufacturer: AD [Analog Devices]

Preliminary Technical Data
As shown in Figure 65 and Figure 66, 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 20 summarizes the HB2 modes.
Table 20. 4× Interpolation Filter Modes (Register 0x1C to
Register 0x1E)
Interpolation
Factor
4
4
4
4
4
4
4
4
Figure 67 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 21 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
Figure 66. HB2, Odd Filter Modes
Pre Mod
0
1
0
1
0
1
0
1
0.4
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
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/2
DAC
Rev. PrA | Page 53 of 73
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)
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Table 21. 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 22 summarizes the filter modes for HB3.
Table 22. 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 67. 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
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DAC
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)
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