AD9874 Analog Devices, AD9874 Datasheet - Page 27

• Manufacturer Part Number: AD9874
• Description: Low Power IF Digitizing Subsystem
• Manufacturer: Analog Devices

Specifications of AD9874

• Resolution (bits): 24bit
• # Chan: 1
• Sample Rate: 26MSPS
• Interface: Ser
• Analog Input Type: Diff-Uni,SE-Uni
• Adc Architecture: Sigma-Delta
• Pkg Type: QFP

Figures 16a and 16b show expanded views of the pass band for the
two possible configurations of the third decimation filter. When
decimating by 60n (K = 0), the pass-band gain variation is 1.2 dB;
when decimating by 48n (K = 1), the pass-band gain variation is
0.9 dB. Normalization of full scale at band center is accurate to
within 0.14 dB across all decimation modes. Figures 17a and 17b
show the folded frequency response of the decimator for K = 0
and K = 1, respectively.
REV. A
Figure 16a. Pass-Band Frequency Response of
the Decimator for K = 0
Figure 16b. Pass-Band Frequency Response of
the Decimator for K = 1
–1
–2
–3
–1
–2
–3
3
2
1
0
3
2
1
0
0
0
NORMALIZED FREQUENCY – RELATIVE TO
NORMALIZED FREQUENCY – RELATIVE TO
PASS-BAND GAIN FREQUENCY = 1.2dB
PASS-BAND GAIN VARIATION = 0.9dB
0.125
0.125
f
f
OUT
OUT
0.250
0.250
–27–
Figure 17a. Folded Decimator Frequency Response for K = 0
Figure 17b. Folded Decimator Frequency Response for K = 1
–100
–120
–100
–120
–20
–40
–60
–80
–20
–40
–60
–80
0
0
0
0
MIN ALIAS ATTN = 87.7dB
MIN ALIAS ATTN = 97.2dB
NORMALIZED FREQUENCY – RELATIVE TO
NORMALIZED FREQUENCY – RELATIVE TO
0.25
0.25
AD9874
f
f
OUT
OUT
0.50
0.50