Third-generation CARMA Correlator FPGA Configurations
Kevin P. Rauch
University of Maryland, College Park 

This memo describes details of the FPGA signal processing and control logic
used in the third-generation (3G) CARMA correlator. This hardware incorporates
a new ultra-wideband A/D converter operating at 20 GHz, sampling the entire
1-9 GHz CARMA IF band for each of 46 inputs (23 antennas x 2 polarizations).
Altera Stratix IV GT FPGAs are used to capture the digitized input signals,
downconvert the IF into 8 individual sub-bands (with selectable bandwidth and
center frequency), and compute cross-correlation lags in real time. Included
here are descriptions of the cross-correlation baseline partitioning; input
data pipelines; digital signal processing components and performance; FPGA
memory map; and control register specification.