ZHCSHD7A January 2018 – April 2020 ADC12DJ2700
PRODUCTION DATA.
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
RESERVED | D4_AP87 | D2_HIGH_PASS | INVERT_SPECTRUM | BOOST | |||
R/W-0000 | R/W-0 | R/W-0 | R/W-0 | R/W-0 |
Bit | Field | Type | Reset | Description |
---|---|---|---|---|
7-4 | RESERVED | R/W | 0000 | RESERVED |
3 | D4_AP87 | R/W | 0 | 0: Decimate-by-4 mode uses 80% alias protection, > 80-dB suppression
1: Decimate-by-4 mode uses 87.5% alias protection, > 60-dB suppression |
2 | D2_HIGH_PASS | R/W | 0 | 0: Decimate-by-2 mode uses a low-pass filter
1: Decimate-by-2 mode uses a high-pass filter. Decimating the high-pass signal causes spectral inversion. This inversion can be undone by setting INVERT_SPECTRUM. |
1 | INVERT_SPECTRUM | R/W | 0 | 0: No inversion applied to output spectrum
1: Output spectrum is inverted This register only applies when the DDC is enabled and is producing a real output (not complex). The spectrum is inverted by mixing the signal with FSOUT / 2 (for example, invert all odd samples). |
0 | BOOST | R/W | 0 | DDC gain control. Only applies to DDC modes with complex decimation.
0: Final filter has 0-dB gain (default) 1: Final filter has 6.02-dB gain. Only use this setting when certain that the negative image of the input signal is filtered out by the DDC, otherwise digital clipping may occur. |