This section provides descriptions of the data elements in each of the binary tables in the output format. An ordered list of the axes over which each table ranges is also provided, although it should be remembered that the lists only represent the typical cases and are not restrictions in the format.
- quantity
Timestamp at the middle of the integration.
![[Note]](images/note.png)
Note The analogous quantity in the ALMA binary format marks the centroid of the actual integration interval, taking into account data blanking.
- units
Modified Julian Date plus fractional day
- element size
16 bytes
- data type
double precision floating point pair
Tentative data type.
- axes (typical)
baseline, baseband, spectral window
Note that there are two supported formats for this table: a
simple table of elements (similar to every other table), or
a table of index values to be used in conjunction with a
lookup table. When using a lookup table, the lookup table is
stored as the lut child
element of the actualDurations child
element of the sdmDataheader element.
- quantity
Integration duration (specifically not including lost data). A special usage is allowed for coarse-grained flagging, which is signified by using a negative value for the duration.
- units
seconds
- element size
8 bytes by default, but may be otherwise through the use of a lookup table.
- data type
Double precision floating point; or, in the case of a mapping defined by a lookup table, an integer-valued bitstring that maps to a double precision floating point value.
- axes (typical)
baseline, baseband, spectral window, bin, APC, spectral channel, polarization product
- quantity
Baseline-based flags that occur during the integration.
- units
undecided (bitfield?)
- element size
4 bytes
- data type
unsigned integer (or N/A)
- axes (typical)
baseline, baseband, spectral window, bin, APC, spectral channel, polarization product
- quantity
Lag zero values.
- units
undecided
- element size
2 × 4 bytes
- data type
complex single precision floating point
- axes (typical)
baseline, baseband, spectral window, bin, APC, polarization product
- quantity
Cross-correlation data; may be either lag spectra or lags.
- units
undecided
- element size
2 × (2 or 4 bytes), depending on value of
typeattribute ofcrossDataheader element- data type
complex single precision floating point or complex integer, depending on value of
typeattribute ofcrossDataheader element- axes (typical)
baseline, baseband, spectral window, bin, APC, spectral channel, polarization product