An Open Source RFSoC-based Readout Electronics System for Arrays of Kinetic Inductance Detectors and Superconducting Resonators

We present a novel readout electronics system for large arrays of superconducting electromagnetic resonators, such as kinetic inductance detectors (KIDs), based on a Radio Frequency System on Chip (RFSoC) architecture. Each channel in the readout system is designed for frequency division multiplexing of up to 1024 high quality factor resonances placed on a single microwave transmission line at unique frequencies within a 512 MHz bandwidth. We describe the design of the digital and analog signal processing chains for the implementation of a two-channel 2048-resonator system on the Xilinx ZCU111 RFSoC evaluation board in combination with a custom intermediate frequency (IF) system to convert the RFSoC band to higher frequencies up to 4 GHz. We also detail an associated software interface that provides a range of tools commonly utilized for characterizing KID resonators and for operating them as part of a photometric millimeter-wave imager. We additionally provide noise characterizations of the individual readout components, along with the complete readout system in isolation and in operation to readout KID resonators.