Abstract
Modern digital radio astronomy receivers produce increasingly wide-bandwidth, high bit-rate data streams that necessitate the development of flexible, scalable, and maintainable back-end processing and recording systems. Historically, such back-end instrumentation has been tightly coupled to telescope observing modes, limiting reuse between observatories and science cases.
We present the Effelsberg Direct Digitisation (EDD) back-end framework, a software-defined architecture for constructing real-time radio astronomy back ends on commodity off-the-shelf computing infrastructure. We describe its design, implementation, supported observing modes, and operational deployments.
EDD separates a common core framework from plug-in-provided observing capabilities. The core provides orchestration, telescope interfaces, pipeline lifecycle management, monitoring, and deployment tooling, while plug-ins implement processing pipelines for specific observing modes. The framework is designed to support both single-dish and interferometric instruments through site-specific configuration and plug-in selection.
EDD currently supports spectroscopy and spectropolarimetry, pulsar timing and searching, baseband recording, very long baseline interferometry, correlation, and beam forming. Operational deployments include the Effelsberg 100-m telescope, the SKA-MPI prototype dish, the Thai National Radio Telescope, and the ARGOS interferometric prototype array. We show that when coupled with in-receiver digitisation, the EDD back end at Effelsberg provides sim30% improvement in pulsar time-of-arrival estimation compared with previous instruments, given the same observing bandwidth and integration time.
EDD provides a reusable open-source framework for developing and operating real-time radio astronomy back ends. By separating common services, observing-mode plug-ins, and site-specific configuration, it allows back-end capabilities to be deployed across heterogeneous telescope environments and provides a community resource for broadband radio astronomy instrumentation.