Datasheet

AD9122
Rev. B | Page 38 of 60
Half-Band Filter 3 (HB3)
Table 17 summarizes the HB2 and HB3 modes.
HB3 has eight modes of operation that function the same as
HB2. The primary difference between HB2 and HB3 is the
filter bandwidths.
Table 17. HB2 and HB3 Filter Modes
Mode f
CENTER
f
MOD
Input Data
0 DC None Real or complex
Figure 56 shows the pass-band filter response for HB3. 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 19 shows the pass-band flatness
and stop-band rejection supported by the HB3 filter at different
bandwidths.
1 f
IN
/4 None Complex
2 f
IN
/2 None Complex
3 3f
IN
/4 None Complex
4 f
IN
f
IN
Real or complex
5 5f
IN
/4 f
IN
Complex
6 3f
IN
/2 f
IN
Complex
7 7f
IN
/4 f
IN
Complex
Figure 55 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 18 shows the pass-band flatness
and stop-band rejection supported by the HB2 filter at different
bandwidths.
0.02
0
–0.02
–0.04
–0.06
–0.08
–0.10
000.280.240.200.160.120.080.04
MAGNITUDE (dB)
FREQUENCY (× f
IN2
) (Hz)
.32
08281-025
0.02
–0.10
–0.08
–0.06
–0.04
–0.02
0
000.240.200.160.120.080.04
MAGNITUDE (dB)
FREQUENCY (× f
IN3
) (Hz)
.28
08281-026
Figure 56. Pass-Band Detail of HB3
Table 19. HB3 Pass-Band and Stop-Band Performance by
Bandwidth
Bandwidth (% of f
IN3
)
Pass-Band
Flatness (dB)
Stop-Band
Rejection (dB)
40 0.001 85
40.8 0.0014 80
42.4 0.002
70
45.6 0.0093
60
Figure 55. Pass-Band Detail of HB2
49.8 0.03 50
Table 18. HB2 Pass-Band and Stop-Band Performance by
Bandwidth
Bandwidth (% of f
IN2
)
Pass-Band
Flatness (dB)
55.6 0.1 40
Stop-Band
Rejection (dB)
50 0.001 85
50.8 0.0012 80
52.8 0.0028 70
56 0.0089
60
60 0.0287 50
64.8 0.1877 40