
DAC5674
SLWS148A SEPTEMBER 2003 REVISED OCTOBER 2005
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17
High-Pass/Low-Pass 4
y Interpolation Filter Operation
Figure 18 shows the high-pass/low-pass filter configuration. Images at Fdata IF and 3Fdata + IF can be
selected. Note that the latter image severely attenuates by the sinx/x response. The transition bandwidths of
filter 1 and filter 2 occupy 0.2Fdata. The combination of these transition bands results in an output IF between
0.6
…0.8Fdata.
Input Spectrum
Output of DUC
1st 2x
interpolation
filter
Spectrum after
2x interpolation
2nd 2x
interpolation
filter
Spectrum after
4x interpolation
Fdata
=
Fdac
80 dB of
attenuation
Unwanted images
removed by LPF
80 dB of
attenuation
80 dB of
attenuation
Figure 18. High-Pass/Low-Pass 4
y Interpolation Filter Operation