RFSoC Gen3-Based Software-Defined Radio Characterization for the Readout System of Low-Temperature Bolometers

TL;DR

This paper evaluates the performance of a Gen3 RFSoC-based SDR readout system for low-temperature bolometers, demonstrating its suitability for next-generation superconducting detector readouts with high multiplexing and low noise.

Contribution

It introduces a Gen3 RFSoC-based SDR system for bolometer readout, showing its effective performance and advantages over existing systems.

Findings

Noise and spurious levels are close to cold readout limits

Noise in RF loopback is better than -100 dBc/Hz

System reduces complexity and enhances integration

Abstract

This work reports the performance evaluation of an SDR readout system based on the latest generation (Gen3) of the AMD's Radio Frequency System-on-Chip (RFSoC) processing platform, which integrates a full-stack processing system and a powerful FPGA with up to 32 high-speed and high-resolution 14-bit Digital-to-Analog Converters (DACs) and Analog-to-Digital Converters (ADCs). The proposed readout system uses a previously developed multi-band, double-conversion IQ RF-mixing board targeting a multiplexing factor of approximately 1,000 bolometers in a bandwidth between 4 and 8 GHz, in line with state-of-the-art microwave SQUID multiplexers ($\mu$MUX). The characterization of the system was performed in two stages, under the conditions typically imposed by the multiplexer and the cold readout circuit. First, in transmission, showing that noise and spurious levels of the generated tones are close to the values imposed by the cold readout. Second, in RF loopback, presenting noise values better than -100 dBc/Hz totally in agreement with the state-of-the-art readout systems. It was demonstrated that the RFSoC Gen3 device is a suitable enabling technology for the next generation of superconducting detector readout systems, reducing system complexity, increasing system integration, and achieving these goals without performance degradation.