Improved High-Speed Data Recorder for Superconducting Digital-RF Receivers

Abstract — A superconducting digital-RF receiver with high ingest-rate data recording capability has been developed. The data recorder unit uses standard PC components with state-of-the-art solid-state drives (SSDs) and interfaces with the superconductor analog-to-digital converter (ADC) through a commercial FPGA board. High-speed data ingest rates exceeding 3.2 GBps have been demonstrated successfully with single-bit ADCs clocked up to 27.52 GHz. A continuous recording of 2.5 TB has been achieved using a bank of 12 SSDs. A new graphical user interface featuring single button operation and automatic file naming as well as convenient configuration setting has been developed. Keywords — ADC, digital recording, digital receiver, direct digitization, field programmable gate arrays, digital radio I. I NTRODUCTION Multi-function and modular digital-RF receiver systems that offer data processing and distribution entirely in the digital domain are beneficial for military and commercial radio frequency (RF) applications [1]. Dynamically changing bandwidth requirements can be best supported with flexible multi-channel receiver architectures using direct digitization. This architecture also has the advantage of eliminating the need for analog intermediate frequencies Signal Analysis(IF) Data Recorder (p)along with most analog RF distribution and processing. Digital -RF receiver systems featuring superconductor analogto-digital converters (ADCs) can be clocked at tens of Gigahertz and are a perfectly suitable to cover a wide range of applications. Rapid single flux quantum (RSFQ) integrated circuits with niobium (Nb) Josephson junctions (JJs) are particularly attractive for direct digitization and digital processing of mixed RF signals [2]. Fig. 1 depicts a multi-band digital-RF receiver showing different functions that may be part of a single receiver terminal. For simplicity, each RF spectrum segment is shown as applied to a single ADC. Each ADC can also feed multiple data processing back end chains through the programmable digital switch matrix. All digital back end processing modules can be band-independent and/or programmable. Either the processed or the unprocessed data streams could be passed to one or more data recorder units for simultaneous data collection or data logging. The initial development of the high-speed data recording for superconducting digital-RF receivers was presented previously and near-continuous data recording with only 88 ms of lost data out of 17 minutes was successfully demonstrated [3]. In this paper, we present a substantially improved high-speed data recorder unit with time continuous data recording capabilities for long data acquisitions.