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Pre Beamformer

KeywordValid values or exampleUsed byDescription
HDR_SIZE4096PSRDADARequired by PSRDADA - size of header in bytes (should always be 4096)
POPULATED0 | 1mwax_db2multibeam2db

Used to ensure the beamformer does not read an incomplete file.

0 means the file is not yet complete, 1 means the file is ready for consumption

OBS_ID1244973688mwax-beamdb2filObs_id of this observation
SUBOBS_ID1244973688mwax-beamdb2filGPS second of this part of the observation. Increments in 8 sec intervals
COMMANDCAPTURE | IDLE | QUIT

mwax_db2multibeam2db

mwax-beamdb2fil

CAPTURE - beamform and produce Filterbank output for this subobservation

IDLE - consume but ignore this subobservation. If there is an existing obs_id in progress, finish the FIL files even if they are not complete

QUIT - stop processing and quit immediately

UTC_START2018-10-11-05:26:14

PSRDADA

mwax-beamdb2fil

Required by PSRDADA. This is the UTC start date/time of the subobservation(?). Used by mwax-beamdb2fil to append a human readable date/time to the filename produced.
OBS_OFFSET0 (n seconds since start of observation)

PSRDADA

mwax-beamdb2fil

Required by PSRDADA. mwax-beamdb2fil uses this to check the ringbuffer block vs expected duration if we hit the end of a block prematurely.

NBIT

8mwax_db2multibeam2dbBits per sample (should always be 8)
NPOL2

mwax_db2multibeam2db

Polarisations per tile (i.e. rf_chains) (should always be 2)

NTIMESAMPLES51200mwax_db2multibeam2dbNumber of timesamples in each input sub-block of a subobservation (nominally sub-blocks are 40 ms)
NINPUTS256 | n rfinputsmwax_db2multibeam2dbNumber of signal paths present in the input subobservation file, to be beamformed

APPLY_PATH_WEIGHTS

0 | 1mwax_db2multibeam2dbShould scalar path weights be applied during beamforming (for gain normalisation and/or sub-arraying)
APPLY_PATH_DELAYS0 | 1mwax_db2multibeam2dbShould fractional path delays be applied during beamforming (for phasing up to a specified pointing direction)
NUM_INCOHERENT_BEAMSNI

mwax_db2multibeam2db

mwax-beamdb2fil

Number of incoherent beams to form (from 0 to the maximum supported by the hardware)
INCOHERENT_BEAM_NN_CHANNELS*

1 - 1280000

mwax_db2multibeam2db

mwax-beamdb2fil

Number of fine channels in beamformed output for incoherent beam number NN


INCOHERENT_BEAM_NN_TIME_INTEG*

1 - 1280000

mwax_db2multibeam2db

mwax-beamdb2fil

Time-scrunch factor for the beamformed output (number of input time samples integrated per output time sample) for incoherent beam number NN
NUM_COHERENT_BEAMSNC

mwax_db2multibeam2db

mwax-beamdb2fil (future)

Number of coherent beams to form (from 0 to the maximum supported by the hardware)

TRANSFER_SIZE

n bytes

PSRDADA

mwax_db2multibeam2db

Total number of bytes of input data for one subobservation (of nominally 8 seconds)
EXPOSURE_SECS8 (in incremements of 8 seconds)mwax-beamdb2filDuration of observation in seconds
COARSE_CHANNEL76 (0 - max receiver channel number == 255)mwax-beamdb2filReceiver channel number 
SECS_PER_SUBOBS8

mwax_db2multibeam2db

mwax-beamdb2fil

Number of seconds per subobservation

UNIXTIME

1539235574Not usedUnix time of the start of this observation. This field is used by mwax-beamdb2fil to provide a UNIX timestep in the filename of the fil files.
UNIXTIME_MSECNot usedUnix time milliseconds offset of the start of this observation. This will always be 0 with the current setup, but is here for completeness.
BANDWIDTH_HZ1280000mwax-beamdb2filCoarse channel passband width in Hz, i.e. the channel spacing

SAMPLE_RATE

1280000mwax_db2multibeam2dbSample rate of input data in samples/s (whether critically-sampled or oversampled)
MC_IP0.0.0.0mwax-beamdb2filMulticast IP for this coarse channel (for debug purposes)
MC_PORT0mwax-beamdb2filMulticast port for this coarse channel (for debug purposes)
MC_SRC_IP0.0.0.0No used (yet)Multicast source IP of data for this coarse channel (for debug purposes)

Post Beamformer changes

KeywordValid values or exampleUsed byDescription

NBIT

32mwax-beamdb2filBits per sample (should always be 32)
NPOL1 | 2

mwax-beamdb2fil

Coherent beams have 2 polarisations

Incoherent beams can optionally have both polarisations combined, so the output may have 1 or 2 polarisations

TRANSFER_SIZE

n bytes

mwax-beamdb2fil

Total number of bytes of output data (the sum of all bytes for all beams) for this 8 second subobservation. Calculated by:

bytes = ????

* Note NN starts at 01 and goes up to the number of beams N

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