Pre-correlator
| Keyword | Valid values or Example | Used By | Description |
|---|---|---|---|
| HDR_SIZE | 4096 | PSRDADA | Required by PSRDADA - size of header in bytes (should always be 4096) |
| POPULATED | 0 | 1 | mwax-correlator | Used to ensure the correlator does not read an incomplete file. 0 means the file is not yet complete, 1 means the file is ready for consumption |
| OBS_ID | 1244973688 | mwax-db2fits | Obs_id of this observation |
| SUBOBS_ID | 1244973688 | mwax-db2fits | GPS second of this part of the observation. Increments in 8 sec intervals |
| COMMAND | CAPTURE | IDLE | QUIT | mwax-db2fits | CAPTURE - correlate and produce FITS output for this subobservation IDLE - consume but ignore this subobservation. If there is an existing obs_id in progress, finish the FITS file even if it is not complete QUIT - process this data block, then quit. |
| UTC_START | 2018-10-11-05:26:14 | PSRDADA | Required by PSRDADA. This is the UTC start date/time of the observation (NOT subobservation) |
| OBS_OFFSET | 0 ?? | PSRDADA | Required by PSRDADA. I believe this is the number of seconds (or bytes?) offset from the start of the observation |
NBIT | 8 | mwax-correlator | Bits per sample |
| NPOL | 2 | mwax-correlator mwax-db2fits | Polarisations per tile (i.e. rf_chains) |
| NTIMESAMPLES | 51200 | mwax-correlator | Number of timesamples per 200 ms "gulp" of the correlator |
| NINPUTS | 256 | n rfinputs | mwax-correlator | Number of tiles involved in observation |
| NINPUTS_XGPU | 256 | n rfinputs in multiples of 16 | mwax-correlator | Number of tiles, rounded up to nearest multiple of 16 for XGPU |
APPLY_PATH_WEIGHTS | 0 | 1 | mwax-correlator | Should weights be applied in precorrelator |
| APPLY_PATH_DELAYS | 0 | 1 | mwax-correlator | Should delays be applied |
| INT_TIME_MSEC | 200 - 8000 | mwax-correlator mwax-db2fits | Correlator mode integration time (milliseconds) |
| FSCRUNCH_FACTOR | 40 (1 - 5120) | mwax-correlator | Correlator frequency scrunch factor: number of ultrafine 250 Hz fine channels to average togeter |
| APPLY_VIS_WEIGHTS | 0 | 1 | mwax-correlator | Should weights be applied to output visibilities |
TRANSFER_SIZE | 5269094400 | mwax-correlator | Total number of bytes of input data for this 8 second subobservation |
PROJ_ID | G0008 | mwax-db2fits | Project ID of observation |
| EXPOSURE_SECS | 8 (in incremements of 8 seconds) | mwax-db2fits | Duration of observation in seconds |
| COARSE_CHANNEL | 76 (0 - max receiver channel number == 255) | mwax-db2fits | Receiver channel number |
| CORR_COARSE_CHANNEL | 9 | (1 - coarse channel max) | mwax-db2fits | Correaltor channel number - which correlator channel "index" is this? e.g. first channel would be 1. In a 24 channel system, last channel would be 24. This would map to gpubox01-24 in the legacy Correlator |
| SECS_PER_SUBOBS | 8 | mwax-db2fits | Number of seconds per subobservation |
UNIXTIME | 1539235574 | mwax-db2fits | Unix time of the start of this observation. This field is used by mwax-db2fits to provide a UNIX timestep for each integration throughout the observation. |
| UNIXTIME_MSEC | 0 | mwax-db2fits | Unix time milliseconds offset of the start of this observation. This will always be 0 with the current setup, but is here for completeness. |
FINE_CHAN_WIDTH_HZ | 10000 | mwax-db2fits | Correlator output fine channel width in Hz |
| NFINE_CHAN | 128 | mwax-db2fits | Correlator output number of fine channels |
| BANDWIDTH_HZ | 1280000 | mwax-db2fits | Coarse channel width in Hz |
SAMPLE_RATE | 1280000 | mwax-correlator | Sample rate of input data |
| MC_IP | 0.0.0.0 | mwax-db2fits | Multicast IP for this coarse channel |
| MC_PORT | 0 | mwax-db2fits | Multicast port for this coarse channel |
| MC_SRC_IP | 0.0.0.0 | mwax-db2fits | Multicast source IP of data for this coarse channel |
Post Correlator changes
| Keyword | Valid values or Example | Used By | Description |
|---|---|---|---|
NBIT | 32 | mwax-db2fits | Bits per complex visibility component (real | imaginary) |
TRANSFER_SIZE | n bytes | mwax-db2fits | Total number of bytes of output data for this 8 second subobservation. Calculated by: bytes = visibilities + weights visibilities = integrations * baselines * fine channels * polarisations * bytes_real * bytes_imaginary weights = integrations * baselines * polarisations * bytes_real |