CONFIG_DESCRIPTION Configuration description.

Name

Format

Units

Measure

Comments

Columns

Key

PROCESSOR_ID

Int Processor identifier

Data description

NUM_ANTENNA

Int Number of antennas Na in the collection

NUM_BASEBAND

Int Number of basebands Nbb in the collection

NUM_SUBBAND

Int( Nbb) Number of ”SUBBANDs” Nsw for each baseband

Data

ANTENNA_ARRAY

Int( Na) Antenna collection

FEED_LIST

Int( Na) Feed collection

PHASED_ARRAY_LIST

Int( Na) Phased array collection

DATA_DESCRIPTION_ARRAY

Int( sum 1 Nbb Nsw) Data description collection

SWITCH_CYCLE_LIST

Int( Nbb) Switch cycle collection

CORRELATION_MODE

Int Correlation mode Ncm

Flags

FLAG_ANTENNA

Bool( Na) Antenna flag collection

Notes: This table sets a referential constraint in the AEDF. It defines the shape of the associated data cell in the MAIN table where it is indexed directly by the CONFIG_DESCRIPTION_ID identifier. The number of identifiers in the DATA_DESCRIPTION_ARRAY collection is sum 1 Nbb Nsw. The collections in this table contain ordered sequences of elements to describe how the data are organized in the data cell (note that any identifier must appear only once in a collection of type array).
PROCESSOR_ID
Processor identifier (> 0) providing a direct index into the PROCESSOR sub-table row number. This identifier allows to distinguish data originating from correlator of different design. Examples: ACA or dedicated single-dish antennas in case these antennas would have specific correlators.
NUM_ANTENNA
Number of antennas in a collection. This collection may correspond to an entire array or to a sub-array.
NUM_BASEBAND
Number of basebands Nbb in the collection
NUM_SUBBAND
Number of “subbands” Nsw for each baseband. Note that this number may not correspond to the number of correlator subbands in the baseband as several may be stitched together. NUM_SUBBAND must be used to represent the number Nsw of spectral windows after the stitching operations.
ANTENNA_ARRAY
ANTENNA collection. It contains an ordered sequence of ANTENNA_ID identifiers to define the antenna (sub-)array. This information is required to know the form of the data-cell object. Example: consider a sub-array of 4 antennas, Na= 4, with their respective identifiers ANTENNA_ID 3 7 70 and 30. In this case the data-cell contains successively the data for the pairs 3-7, 3-70, 7-70, 3-30, 7-30, 70-30, 3-3, 7-7, 70-70 and 30-30, this order1 being determined by the position of the identifiers in the sequence. As illustrated with this example it is seen that the data-cell contains firstly the cross-correlated data and then the auto-correlated data. The number of atomic data per pair corresponds to NapcNc sum i=1i=NbbNbin(i) sum j=1Nsw(i)Nf(i,j) these data being stored 2 or 4 bytes integers (see item BIT_SIZE in the MAIN table) which can be converted into float-complex or float using the item SCALE_FACTOR (also in the MAIN table).
Note: see item PHASED_ARRAY_LISTin case of phased arrays.
FEED_LIST
List of FEED_ID identifiers. This list is a collection with the same number of elements as in the ANTENNA_ARRAY collection. Each element corresponds to a FEED_ID identifier. In almost all cases, for ALMA, FEED_ID = 0 because there is in general only one feed for the pair of keys ANTENNA_ID, SPECTRAL_WINDOW_ID. In a few exceptional cases one could have however two tuples with FEED_ID = 0 and 1 respectively for a given SPECTRAL_WINDOW_ID, this occuring when one would observe in a spectral region where two adjacent receiver bands overlap, e.g. with the bands 2 and 3 of ALMA.
PHASED_ARRAY_LIST
List of phased array numbers. This list is a collection with the same number of elements as in the ANTENNA_ARRAY collection. Each element corresponds to a phased (sub)array number. A value of -1 means that the corresponding antenna is not co-phased with other antennas. Taking the example given for the item ANTENNA_ARRAY , if the list PHASED_ARRAY_LIST is (-1 -1 -1 -1) none of the antennas with their identifiers 3, 7, 70 and 30 are co-phased. This would also be the case if each element is unique in the list as e.g. with a list (0 1 2 3). If several elements have the same value then the corresponding antennas are co-phased and assigned to the subarray number corresponding to that value. For example with (0 0 0 1) the antennas with the identifiers 3, 7 and 70 are co-phased and the co-phased result is cross-correlated with the antenna 30, provided that CORRELATION_MODE is 0 or 2. The order of the elements in the ANTENNA_ARRAY collection must be such that the co-phased antennas appear in adjacent positions in this PHASED_ARRAY_LIST list. The positions of the cross-correlated data in the data cell are ordered according to the order in the PHASED_ARRAY_LIST list. With (0 0 0 1), or for a list as (0 0 0 1 1), there is only one baseline, 0-1. With a list like (0 0 0 1 1 2) the cross-correlated data will appear successively for 0-1, 0-2 and 1-2 in the data cell.
DATA_DESCRIPTION_ARRAY
DATA_DESCRIPTION collection of ordered DATA_DESCRIPTION_ID identifiers which defines the ensemble of DATA_DESCRIPTION_ID used by the correlator for the antenna (sub-)array. The order of the elements in this collection gives the sequence of data_descriptions to define the organization of the data in the data cell. Together with the ANTENNA_ARRAY and SWITCH_CYCLE_LIST collections it contributes to determine the form of the data-cell object. This DATA_DESCRIPTION_ARRAY collection defines a domain of integrity in a tri-dimensional space, the axes being the correlator bin axis, the sub-band axis and the baseband axis. The bin axis size may be greater than one, e.g. in case of observations using the frequency-switch mode. The order of these axes is fixed, the coordinates along the bin axis being scanned the first.
SWITCH_CYCLE_LIST
Array of SWITCH_CYCLE_ID identifiers, one per baseband. For a given identifier this provides Nbin which sets the size of the bin axis, for a certain baseband, in the data-cell object. Nbin has to be given for each baseband.
CORRELATION_MODE
Correlation mode. 0 means no auto-correlation i.e. only cross-correlations, 1 means no cross-correlation i.e. only auto-correlations and 2 means both cross-correlations and auto-correlations. For ALMA valid values are restricted to 1 and 2 which can be represented by Ncm.
FLAG_ANTENNA
Flag antenna collection with the same number of elements as for ANTENNA_ARRAY collection.
One element in this collection is TRUE if the data cell in the MAIN table has valid data for the corresponding antenna; does not imply flagging in MAIN .