Basic characteristics of the design of the EVN MkIV data processor include: correlation of up to 16 stations with 16 channels per station, 1 Gb/s recording (via 2 head-stacks 32 tracks/head-stack 16Mb/s/track), and use of either MkIV and VLBA format recordings. Figure 1 shows the data playback units, the station units, the data distributor unit, and control computers. The correlator itself is housed in a separate room out of this view.
The principal science drivers behind the development of the data processor and associated software include the ability to handle continuum dual-polarization observations, spectral line experiments (i.e., providing lots of frequency points and narrow bandwidths to provide high spectral resolution), and phase-reference mapping.