The D-rack contians three components of the signal path: the IF Distributor, the baseband converters (BBCs), and the formatter.

The IF Distributor distributes the four intermediate frequencies across the baseband converters.

The baseband converters select the specific frequency range that contains the astronomical data and extracts it from the 500 - 1000 MHz intermediate frequency.

The formatter takes the data from the baseband converter and formats it, along with the timing information from the C-rack, onto the recording media (tape or disk).