DBBC Plugin Overview

The DBBC plugin implements the EDD backend for VLBI observations at Effelsberg using the Digital Base Band Converter signal path. It receives wideband digitiser data, extracts narrow subbands via GPU-accelerated digital down-conversion, packs the result into VDIF frames, and delivers them to a disk recorder or sends them over the network for real-time correlation.

The plugin provides two pipelines controlled by the EDD Master Controller per observation, and two services that run continuously to bridge external systems.

Pipelines

Pipeline	Entry Point	Purpose
DigitalDownConverter	`edd_ddc_processor`	GPU digital down-conversion of packetizer data
VDIFPacker	`edd_vdif_packer`	VDIF frame packing and disk/network output

Services

Service	Container	Purpose
FieldSystemInterface	`field_system_interface`	KATCP bridge between Field System and EDD
jive5ab	`edd_jive5ab`	VLBI recorder, accepts UDP VDIF from VDIFPacker

Data Flow

        graph LR
    packetizer["MPIFR Packetizer\n4 Gsps ADC"]
    ddc["DigitalDownConverter\npipeline"]
    vdif["VDIFPacker\npipeline"]
    disk["Disk"]
    jive["jive5ab\nservice"]
    fs["Field System\n(telescope control)"]
    fsi["FieldSystemInterface\nservice"]
    mc["EDD Master\nController"]

    packetizer -->|"SPEAD2\nMPIFR_EDD_Packetizer:2"| ddc
    ddc -->|"SPEAD2\nDigitalDownConverter:1"| vdif
    vdif --> disk
    vdif -->|"UDP VDIF"| jive
    fs <-->|"DBBC / Mark5 protocol"| fsi
    fsi <-->|"KATCP"| mc
    mc -->|"configure / start / stop"| ddc
    mc -->|"configure / start / stop"| vdif

Docker Image

Both pipelines and the FieldSystemInterface run inside the edd_dbbc image. jive5ab runs in its own jive5ab image. The images are built by GitLab CI from the Dockerfiles in roles/edd_dbbc/templates/ and roles/jive5ab/templates/ respectively.