SBASAU7C December 2024 – July 2025 ADC3548 , ADC3549
PRODUCTION DATA
This section provides the different decimation filter responses with a normalized ADC sampling rate. The complex filter pass band is approximately 80% (-1dB) with a minimum of 85dB stop band rejection.
The decimation filter responses are normalized to the ADC sampling clock frequency FS and illustrated in Figure 8-23 to Figure 8-52. The responses are interpreted as follows: Each figure contains the filter pass-band, transition band and alias or stop-band as shown in Figure 8-22. 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 8-22 Interpretation
of the Decimation Filter Plots