|NI-SCOPE (English | Japanese)|
The DDC takes a programmable portion of the Nyquist spectrum of the ADC and moves it down to baseband (centered around 0 Hz). This process is performed by first frequency translating the center of the band of interest to 0 Hz. The data is then filtered and decimated to get alias-protected data of the requested bandwidth. The data output from the DDC is stored into memory at this lower sample rate as complex IQ pairs.