In addition to the NCO the DAC38RFxx also has a coarse mixer block capable of shifting the input signal spectrum by the fixed mixing frequencies ±N x fDAC/8. Using the coarse mixer instead of the full mixers will result in lower power consumption.
Treating the two complex channels as complex vectors of the form I(t) + j Q(t), the outputs of the coarse mixer is equivalent to:
Where fCMIX_AB and fCMIX_CD and the fixed mixing frequency selected by fields CMIX_AB or CMIX_CD in register CMIX (8.5.21). The coarse mixer blocks are disabled by setting CMIX_AB and CMIX_CD to 0x0.
The NCO and coarse mixers can be enabled simultaneously, although this is not useful in most cases as the full frequency range can be covered by the NCO.