Characterising the Performance of High-Speed Data Converters for RFSoC-based Radio Astronomy Receivers

TL;DR

This study evaluates the performance of high-speed 12-bit RFSoC data converters for radio astronomy, demonstrating their suitability through extensive measurements and real-time implementation.

Contribution

It provides a comprehensive performance characterization of Xilinx ZU28DR RFSoC data converters for radio astronomy applications, including real-time spectrometer implementation.

Findings

ADC performance meets radio astronomy requirements

Spectral stability over tens of hours confirmed

Performance close to vendor specifications

Abstract

RF system-on-chip (RFSoC) devices provide the potential for implementing a complete radio astronomy receiver on a single board, but performance of the integrated analogue-to-digital converters is critical. We have evaluated the performance of the data converters in the Xilinx ZU28DR RFSoC, which are 12-bit, 8-fold interleaved converters with a maximum sample speed of 4.096 Giga-sample per second (GSPS). We measured the spurious-free dynamic range (SFDR), signal-to-noise and distortion (SINAD), effective number of bits (ENOB), intermodulation distortion (IMD) and cross-talk between adjacent channels over the bandwidth of 2.048 GHz. We both captured data for off-line analysis with floating-point arithmetic, and implemented a real-time integer arithmetic spectrometer on the RFSoC. The performance of the ADCs is sufficient for radio astronomy applications and close to the vendor specifications in most of the scenarios. We have carried out spectral integrations of up to 100 s and stability tests over tens of hours and find thermal noise-limited performance over these timescales.