ZHCSEE2B December 2015 – January 2023 ADS54J66
PRODUCTION DATA
In this configuration, the DDC block includes a selectable N × fS / 16 complex digital mixer (N from –8 to +7) preceding the decimation-by-2 digital filter, so the IQ passband is approximately ±55 MHz (3 dB) centered at N × fS / 16. A positive value for N inverts the spectrum.
The stop-band attenuation is approximately 90 dB for in-band aliases from negative frequencies. The pass-band flatness is ±0.1 dB. Figure 62 shows the filtering operation in DDC mode 5. Table 6 shows corner frequencies of decimation filter in DDC mode 5. Figure 63 and Figure 64 show frequency response of the filter. Figure 7-12 shows the filtering operation in DDC mode 5. Table 7-6 shows corner frequencies of decimation filter in DDC mode 5. Figure 7-13 and Figure 7-14 show frequency response of the filter.
Figure 7-12 Mixing
and Filtering in Mode 5| CORNERS | LOW PASS |
|---|---|
| –0.1 dB | 0.102 × fS |
| –0.5 dB | 0.105 × fS |
| –1 dB | 0.108 × fS |
| –3 dB | 0.113 × fS |
Figure 7-13 Frequency Response for Decimate-by-2, Low-Pass Filter (In Mode 5)
Figure 7-14 Zoomed View of Frequency Response