================================================================ NOTE - THIS IS AN OBSOLETE PAGE KEPT FOR HISTORICAL REASONS ONLY. DO NOT USE INFORMATION ON THIS PAGE FOR VLBA OBSERVING ================================================================ VLBA RECORDING MODES SUPPORTED DURING the MARK 5A TRANSITION All modes shown in this table are supported by the Mark 5A recording sys- tem which is now being phased in across the VLBA. No other modes will be available until the Mark 5B system becomes available. Those former VLBA modes which are no longer supported were used extremely rarely. Users who may find them necessary should contact J. D. Romney to discuss workarounds. ------------------------------------------------------------------------- | | _____ One-Bit Sampling _____ | _____ Two-Bit Sampling _____ | | Ch Msmp| Mode Mbps Fan P S T | Mode Mbps Fan P S T | |---------+------------------------------+------------------------------| | 16 32 | 512-16-1 512 1:4 1 .5 4 | | | 16 16 | 256-16-1 256 1:2 1 .5 2 | 512-16-2 512 1:2 1 .5 4 | | 16 8 | 128-16-1 128 1:2 1 1 1 | 256-16-2 256 1:1 1 .5 2 | | 16 4 | 64-16-1 64 1:2 1 2 1/2 | 128-16-2 128 1:1 1 1 1 | | 16 2 | 32-16-1 32 1:1 2 2 1/4 | 64-16-2 64 1:1 1 2 1/2 | |---------+------------------------------+------------------------------| | 8 32 | 256-8-1 256 1:4 1 1 2 | 512-8-2 512 1:4 1 .5 4 | | 8 16 | 128-8-1 128 1:4 1 2 1 | 256-8-2 256 1:2 1 1 2 | | 8 8 | 64-8-1 64 1:4 1 4 1/2 | 128-8-2 128 1:2 1 2 1 | | 8 4 | 32-8-1 32 1:2 2 4 1/4 | 64-8-2 64 1:2 1 4 1/2 | | 8 2 | 16-8-1 16 1:1 4 4 1/8 | 32-8-2 32 1:1 2 4 1/4 | |---------+------------------------------+------------------------------| | 4 32 | 128-4-1 128 1:4 2 1 1 | 256-4-2 256 1:4 1 1 2 | | 4 16 | 64-4-1 64 1:4 2 2 1/2 | 128-4-2 128 1:4 1 2 1 | | 4 8 | 32-4-1 32 1:4 2 4 1/4 | 64-4-2 64 1:4 1 4 1/2 | | 4 4 | 16-4-1 16 1:2 4 4 1/8 | 32-4-2 32 1:2 2 4 1/4 | | 4 2 | | 16-4-2 16 1:1 4 4 1/8 | |---------+------------------------------+------------------------------| | 2 32 | 64-2-1 64 1:4 4 1 1/2 | 128-2-2 128 1:4 2 1 1/1 | | 2 16 | 32-2-1 32 1:4 4 2 1/4 | 64-2-2 64 1:4 2 2 1/2 | | 2 8 | 16-2-1 16 1:4 4 4 1/8 | 32-2-2 32 1:4 2 4 1/4 | | 2 4 | | 16-2-2 16 1:2 4 4 1/8 | |---------+------------------------------+------------------------------| | 1 32 | | 64-1-2 64 1:4 4 1 1/2 | | 1 16 | | 32-1-2 32 1:4 4 2 1/4 | | 1 8 | | 16-1-2 16 1:4 4 4 1/8 | ------------------------------------------------------------------------- Ch Number of baseband channels. Msmp Sample rate, in Mega-samples per second. Mode Mode name (Aggregate_data_rate-Channels-Bits); append -R or -L if only one polarization is used. Mbps Total recorded bit rate, in Mega-bits per second. 512 Mbps modes record on two tapes simultaneously in VLBA format. Fan Fan out ratio. Maximum fan out for maximum speed up factor. P Number of passes per head position. P <= 4 REQUIRED for Mark 5A. S Processing speedup factor. Halved for 16 channels and/or 512 Mbps because 2 passes are required. T Tape consumption rate, relative to sustainable rate of 128 Mbps. History: "VLBA Observing Modes", VLBA Memo 452 -- J. D. Romney, 85/5/5. "Basic VLBA Recording Modes" -- R. C. Walker, 1994. VLBA "All Modes Test" -- J. D. Romney & V. Dhawan, 94/4/21. Mark 4 column added -- R. C. Walker, 97/5/19. FT001 -- J. D. Romney, A. J. Mioduszewski, H. J. van Langevelde, 97/6/24. FT002 -- A. J. Mioduszewski, 97/9/16. Data rate & spectroscopy warnings added -- J. D. Romney, 98/1/21. FT003 -- J. D. Romney, 98/12/28. FT004 -- J. D. Romney, 99/3/19. General limitations moved to Guidelines -- J. D. Romney, 99/10/21. All 512-Mbps VLBA modes validated -- J. D. Romney, 01/1/5. Mark 5A mode restrictions applied. -- J. D. Romney, 04/12/15.