MPIfR/BKG MKIV CORRELATOR - REPORT TO THE EVN-TOG - 1 APR. 2004 =========================== ===================== =========== GENERAL Current correlator capabilities are listed at: http://www.mpifr-bonn.mpg.de/EVN/MK4CORstatus CORRELATOR HARDWARE > Plans to upgrade to Mark 5B are being discussed between BKG (German mapping authority) and MPIfR. The aim is a total of 12 Mark 5B units for the correlator. CORRELATION SOFTWARE > Works smoothly with Mark 5. Still problems in logs because of incomplete or wrong disk serial numbers. OPERATIONS > The correlator has no backlog. > The correlation factor (correlation/observing) for geodetic observations could be reduced from about 2.5 to 1.5 due to the usage of more and more Mark 5 systems. > The first 6 station Mark 5 observation has been correlated (geodesy). A further decrease in the correlation factor is expected. > Disks (and tapes) from EVN observations are recycled before the next session. > First correlation of data from the new global mm-array will start in May. > Fringe checks via ftp transfer have been done with Mark 5 systems and the correlator. W.Alef CAPABILITIES OF THE BONN MK4 VLBI CORRELATOR Version 11: 11 November 2003 INTRODUCTION The Bonn MK4 VLBI correlator is operated jointly by the MPIfR and GIUB (Bonn) and the BKG (Frankfurt). It has 9 playback units and can correlate up to 16 channels of MK3, MK4 or VLBA formatted data from each in a single correlation pass. The current capabilities are summarised below. For further information contact the Correlator Manager, Walter Alef: =====> walef@mpifr-bonn.mpg.de PLAYBACK UNITS Number available: 9 MK4 tape drives 8 MK5A systems (alternative to a tape drive) Tape types: thick and thin (7 drives optimised for thin) Playback speeds: 80, 160 ips (thin tape); 135, 270 ips (thick tape) (MK5A: up to 1024 Mb/s) SUPPORTED RECORDING Record speeds: 80, 160 ips (thin tape); 135, 270 ips (thick tape) Formats: MK3/MK4/VLBA (MK4/VLBA w/wo barrel roll, data demod.) Sampling: 1 or 2-bit (over-sampling not yet tested) Fan-out: 1:1 1:2 1:4 (fan-in not supported) No. of channels: <= 16, USB and/or LSB (multiple passes supported for >16 channels in MK4IN) Bandwidth/channel: ....2, 4, 8, 16 MHz Signals: mono, dual frequency or dual polarisation Modes: MK3: B, C, BB, CC; A, AA (in 2 passes) 128-16-1 128-16-2 128-8-1 128-8-2 128-4-1 128-4-2 128-2-2 256-16-1 256-16-2 256-8-1 256-8-2 256-4-2 512-16-2 512-8-2 (with 1 head using 2 passes) (and lower bit-rates at 80 ips) MK5A only: 1024-16-2 (all modes in 1 pass) CORRELATION Geometric model: CALC 8 Number of boards: 16 (DSP not yet implemented) Phase cal: single tone extraction at selectable frequency (multi-tone phase-cal not implemented) Pre-average times: 0.2 -> 5 s (default 2 s; 60/N s, N an integer; short integration times not with full correlator capacity) Lags per channel: 32 minimum (==> frequency resolution = BW/16) 1024 tested; 4096 maximum Maximum output: 9 stations: 36 baselines, 16 channels, 32 lags with ACF (no cross polarisation) 8 stations: 28 baselines, 16 channels, 32 lags with ACF and full cross polarisation Multiple streams: Maximum of 4 independent correlations for simultaneous correlation of sub-nets, etc. Multiple passes: Supported for >9 stations (up to 13 in 3 passes) Fringe-fit: Off-line FOURFIT run. (Dual frequency in single execution: dual/cross-polsn. in multiple executions) AUXILIARY FILES Correlator control: Observing VEX file (from SKED or SCHED) Station logs: Standard FS logs, VLBA logs GPS data: EVN and VLBA standard formats ARCHIVE AND EXPORT Archive medium: DDS2, DDS3 and DDS4 DAT Archive content: root, type1('51'), type2('52'), type3(station-based) Post-cor. software: HOPS data inspection, re-processing software interface to CALC/SOLV interface to AIPS using task MK4IN via HOPS with automatic application of phase-cal and other corrections, transfer of FOURFIT solutions (AIPS task BLAPP). (Maintained by R.Porcas at: http://www.mpifr-bonn.mpg.de/EVN/MK4CORstatus)