  We present the ARAGORN front-end, a cost-optimized, high-density
Time-to-Digital Converter platform. Four Xilinx Artix-7 FPGAs implement 384
channels with an average time resolution of 165 ps on a single module. A fifth
FPGA acts as data concentrator and generic board master. The front-end features
a SFP+ transceiver for data output and an optional multi-channel optical
transceiver slot to interconnect with up to seven boards though a star
topology. This novel approach makes it possible to read out up to eight boards
yielding 3072 input channels via a single optical fiber at a bandwidth of 6.6
Gb/s.
