ADC34RF72 datasheet(39/74 Pages) TI2

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7.3.5.5.3 Decimation Filter Response

This section provides the different decimation filter responses with a normalized ADC sampling rate. The

complex filter pass band is approximately 80% (−0.1dB) of the decimated bandwidth with a minimum of 85dB

stop band rejection.

The decimation filter responses are normalized to the ADC sampling clock frequency FS. One example

(decimation by 4) is illustrated in Figure 7-28 and Figure 7-29. The filter responses for all other decimation

filter plots are available in the product folder.

The decimation filter plots are interpreted as follows: Each figure contains the filter pass-band, transition bands

and alias or stop-bands as shown in Figure 7-27. The x-axis shows the offset frequency (after the NCO

frequency shift) normalized to the ADC sampling rate FS.

For example, in the divide-by-4 complex setup, the output data rate is FS / 4 complex with a Nyquist zone of FS /

8 or 0.125 × FS. The transition band (colored in blue) is centered around 0.125 × FS and the alias transition band

is centered at 0.375 × FS. The stop-bands (colored in red), which alias on top of the pass-band, are centered at

0.25 × FS and 0.5 × FS. The stop-band attenuation is greater than 85dB.

Figure 7-27. Interpretation of the Decimation Filter Plots

Figure 7-28. Decimation by 4 Filter Response

Figure 7-29. Decimation by 4 Passband Ripple

Response

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ADC32RF72

SBASAL2 – NOVEMBER 2025

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ADC34RF72 数据表(PDF) 39 Page - Texas Instruments