Datasheet

AD9125
Rev. 0 | Page 34 of 56
Table 18 summarizes the HB2 and HB3 modes.
Table 18. HB2 and HB3 Filter Mode Summary
Mode f
CENTER
f
MOD
Input Data
0 DC None Real or complex
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 6f
IN
/4 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, not by
the pass-band flatness. Table 19 shows the pass-band flatness
and stop-band rejection that the HB2 filter supports at different
bandwidths.
0.02
0
–0.02
–0.04
–0.06
–0.08
–0.10
000.280.240.200.160.120.080.04
GAIN (dB)
NORMALIZED FREQUENCY (× f
IN2
)
.32
09016-025
Figure 55. Pass-Band Detail of HB2
Table 19. HB2 Pass-Band Flatness and Stop-Band Rejection
Complex Bandwidth
(% of f
IN2
)
Pass-Band
Flatness (dB)
Stop-Band
Rejection (dB)
50 0.001 85
50.8 0.0012 80
52.8 0.0028 70
56.0 0.0089 60
60 0.0287 50
64.8 0.1877 40
Half-Band Filter 3 (HB3)
HB3 has eight modes of operation that function the same as
HB2. The primary difference between HB2 and HB3 is the filter
bandwidths.
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, not by
the pass-band flatness. Table 20 shows the pass-band flatness
and stop-band rejection that the HB3 filter supports at different
bandwidths.
0.02
0
–0.02
–0.04
–0.06
–0.08
–0.10
000.240.200.160.120.080.04
GAIN (dB)
NORMALIZED FREQUENCY (× f
IN3
)
.28
09016-026
Figure 56. Pass-Band Detail of HB3
Table 20. HB3 Pass-Band Flatness and Stop-Band Rejection
Complex 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
49.8 0.03
50
55.6 0.1 40