EVN MkIV DATA PROCESSOR AT JIVE Operational & Development Status Sheet 18/06/2003 OPERATIONAL HOURS: Operational hours: 80/week. Typically 35% of time is spent testing new features and bug fixes (prior to having exhausted the queue of experiments available to correlate in early May). CURRENTLY OPERATIONAL SYSTEM: All 16 drives are available for thick and thin tape playback; they are equipped with a single (read)head. MkV: 4 Mk5A systems available Supported speeds: Single-speed (80ips thin, 135ips thick) and double-speed (160ips thin, 270ips thick) available for tape (i.e., 4 or 8 Mb/s/track). Speed-up (playback speed different from recording speed) not currently operational, but being implemented. Quadruple-speed playback (i.e., 16 Mb/s/track) is available from disk. Playback heads: Tape playback units have 1 mounted (read) head, providing 32-track capability in 1 pass. Disks can also read 32 tracks at the current moment, and development work on the control software to use 64 tracks from disk is underway. MkIV, VLBA, MkIII playback without barrel-roll supported (including modulation for VLBA format). Data streams: Fan-outs of 1:1, 1:2, or 1:4; using 1 or 2 bit recording; oversampling operational. Fan-in not planned. Maximum total data rates: Tape: 512 Mb/s - 64 tracks at 8 Mb/s/track; correlated in 2 passes. Disk: 1 Gb/s - 64 tracks at 16 Mb/s/track; (currently) correlated in 2 passes. Bandwidths: 500kHz, 1 MHz (both via oversampling), 2, 4, 8, 16 MHz. Upper, Lower, or Dual sideband; Single or Dual Polarization. CORRELATION: All 32 boards (1024 chips) operational (using on-board DSP). Visibility integration times of 0.25s tested, in principle multiples of 0.0625s are possible, but 1/64s correlator frames still undergoing testing (see also restrictions on read-out capacity). Minimum integration time for read-out entire correlator: 1 sec (1.5 MB/s); integration time can be traded against spectral resolution down to 0.25s (i.e., use of only 1/2 or 1/4 of the correlator capacity permits integrations of 1/2s or 1/4s, respectively). Maximum spectral points/baseline when using the entire correlator: 16 telescopes: 512 8 telescopes: 2048 4 telescopes: 4096 These spectral points must be spread evenly over the sub-band/polarization products correlated per baseline, with a minimum of 16 spectral points per individual product. There is an additional maximum of 16 (sub-bands)*(parallel polarizations) arising from the station-units. Correlation of projects with more than 16 stations recording simultaneously is possible by processing in multiple passes and automatically merging the data. For 17-24 stations, 3 passes would be required to ensure coverage of all baselines. Correlation of projects using 64 tracks currently possible by making two passes. For tape-based experiments, this would correspond to two-head recordings at 512Mb/s. Disk-only experiments could record 512Mb/s at 16Mb/s/track using only 32 tracks, which we could correlate in 1 pass; full 1Gb/s recordings would now require 2 passes (use of 64 tracks from disk is under development). Creation of correlation-control files for disk and mixed disk-tape projects from the VEX schedule and field-system logs is implemented and tested regularly, keeping up with new versions. Logistics are now in place to support multiple projects per disk-pack. Speed-up correlation still in development. No automated handling of sub-netting yet (as scheduled, GJ010A sub-nets; a manual scheme for handling this has been conceived, but correlation has not yet been attempted). No phase-cal detection yet. OUTPUT DATA FORMAT: Data is transfered to aips++ measurement sets (MS version 2) and exported in IDI Fits, ready for processing in classic AIPS (similar information content as VLBA data). Correlator Archive consists of raw data files in JIVE specific format. The new EVN Archive at JIVE provides access to the standard-plots, pipeline results, and FITS data (the latter subject to an 18-month delay for public release). A further link to the EVN Feedback Facility is planned soon. In aips++ standard flagging is done (rate zero crossings, playback quality threshold). A better amplitude compensation for the 2-bit van Vleck correction is also now done in aips++ (based on observed station sampler statistics per subband/polarization, as derived from the auto-correlation (lag) spectrum at each integration). ENHANCEMENT PROJECTS: Description Status -------------------------------------------------------------------------- Recirculation Development in progress PCInt: data rate 10-160 MB/s Development in progress Speed-up Development in progress Pulsar gating Designed LIST OF MODES: The following modes were processed successfully: First column indicates the number of projects, followed by the number of bands, filter used, sample rate, number of bits, polarization, sideband, fan-out, tape speed, NRAO notation equivalent. 5 16x8MHz 16Ms/s 2b Dpol Lsb 1:2 160ips 512-16-2 21 8x8MHz 16Ms/s 2b Dpol Usb 1:2 160ips 256-8-2 1 8x8MHz 16Ms/s 2b Rpol Dsb 1:2 160ips 256-8-2 1 8x8MHz 16Ms/s 2b Lpol Usb 1:2 160ips 256-8-2 2 8x8MHz 16Ms/s 2b Dpol Usb 1:2 270ips 256-8-2 1 28x2MHz 4Ms/s 1b Rpol Dsb 1:1 135ips 112-28-1 1 8x4MHz 8Ms/s 2b Dpol Usb 1:1 160ips 128-8-2 1 8x4MHz 8Ms/s 2b Dpol Lsb 1:2 80ips 128-8-2 1 8x4MHz 8Ms/s 2b Dpol Usb 1:1 267ips 128-8-2 3 8x4MHz 8Ms/s 2b Dpol Usb 1:2 80ips 128-8-2 1 8x4MHz 8Ms/s 2b Dpol Usb 1:1 270ips 128-8-2 2 8x4MHz 8Ms/s 2b Dpol Usb 1:2 135ips 128-8-2 2 8x8MHz 16Ms/s 1b Dpol Usb 1:4 135ips 128-8-1 3 8x8MHz 16Ms/s 1b Dpol Usb 1:4 80ips 128-8-1 24 4x8MHz 16Ms/s 2b Dpol Usb 1:4 135ips 128-4-2 3 4x8MHz 16Ms/s 2b Lpol Usb 1:4 135ips 128-4-2 36 4x8MHz 16Ms/s 2b Dpol Usb 1:4 80ips 128-4-2 2 8x2MHz 4Ms/s 2b Dpol Usb 1:1 80ips 64-8-2 1 8x2MHz 4Ms/s 2b Dpol Usb 1:1 135ips 64-8-2 12 4x4MHz 8Ms/s 2b Dpol Usb 1:2 135ips 64-4-2 3 4x4MHz 8Ms/s 2b Dpol Usb 1:2 80ips 64-4-2 1 4x4MHz 8Ms/s 2b Dpol Usb 1:1 267ips 64-4-2 1 4x8MHz 16Ms/s 1b Dpol Usb 1:1 135ips 64-4-1 3 2x8MHz 16Ms/s 2b Dpol Usb 1:4 135ips 64-2-2 1 2x8MHz 16Ms/s 2b Dpol Usb 1:4 80ips 64-2-2 2 6x2MHz 4Ms/s 2b Dpol Usb 1:1 80ips 48-6-2 6 4x500kHz 4Ms/s 2b Dpol Usb 1:1 80ips 32-4-2 1 4x500kHz 4Ms/s 2b Dpol Usb 1:1 135ips 32-4-2 2 4x2MHz 4Ms/s 2b Dpol Usb 1:1 80ips 32-4-2 2 2x4MHz 8Ms/s 2b Dpol Usb 1:2 135ips 32-2-2 1 2x4MHz 8Ms/s 2b Dpol Usb 1:2 135ips 32-2-2 1 2x4MHz 8Ms/s 2b Dpol Usb 1:2 80ips 32-2-2 2 2x2MHz 4Ms/s 2b Dpol Usb 1:1 80ips 16-2-2 1 2x2MHz 4Ms/s 2b Dpol Usb 1:1 135ips 16-2-2