SBASB21 September 2024 DDS39RF12 , DDS39RFS12
PRODUCTION DATA
Each DUC has an NCO block that is capable of phase continuous frequency hopping and phase coherent frequency hopping through a NCO with 64-bit frequency and 16-bit phase words. The NCO provides the complex sinusoid that is used for the complex mixing operation. The NCOs can also be used with DDS mode to generate a tone without using the DUC filter path.
The NCO updates modes are either Phase-continuous (see Phase-continuous NCO Update Mode), Phase-coherent (see Phase-coherent NCO Update Mode or Phase-sync (see Phase-sync NCO Update Mode).
The NCO frequency is written to the NCO frequency word register setting through either the standard SPI interface or through the Fast Reconfiguration (FR) interface, which allows for faster frequency updates. The frequency update occurs either as soon as the new frequency word is written or once triggered by the chosen trigger source. Available trigger sources are a SPI register, the SYSREF signal or by replacing the LSB of the I input signal with a sync signal (determined by the NCO_SYNC_SRC register).