The PORT table describes the SpectralProcessor set up and which IF inputs (samplers) have been used. An example header, plus ascii listing of typical table data, is given below:
PORT Binary Tables Extension: Header ------------------------------------------------------------------------------- XTENSION= 'BINTABLE' / binary table extension BITPIX = 8 / 8-bit bytes NAXIS = 2 / 2-dimensional binary table NAXIS1 = 118 / width of table in bytes NAXIS2 = 2 / number of rows in table PCOUNT = 0 / size of special data area GCOUNT = 1 / one data group (required keyword) TFIELDS = 5 / number of fields in each row TTYPE1 = 'BANK_A' / label for field 1 TFORM1 = '1A ' / data format of field: 1-byte CHAR TUNIT1 = 'none ' / physical unit of field TTYPE2 = 'PORT_A' / label for field 1 TFORM2 = '1I ' / data format of field: 2-byte INTEGER TUNIT2 = 'INDEX ' / physical unit of field TTYPE3 = 'BANK_B' / label for field 1 TFORM3 = '1A ' / data format of field: 1-byte CHAR TUNIT3 = 'none ' / physical unit of field TTYPE4 = 'PORT_B' / label for field 2 TFORM4 = '1I ' / data format of field: 2-byte INTEGER TUNIT4 = 'INDEX ' / physical unit of field TTYPE5 = 'TAPER ' / TFORM5 = '8A ' / TUNIT5 = 'none ' / physical unit of field TTYPE6 = 'FREQRES ' / TUNIT6 = 'HZ ' / TFORM6 = '1D ' / TTYPE7 = 'BANDWDTH' / TUNIT7 = 'HZ ' / TFORM7 = '1E ' / TTYPE8 = 'ATTENUAT' / TFORM8 = '1E ' / TUNIT8 = 'dBm ' / TTYPE9 = 'FASTTIME' / TUNIT9 = 'SECONDS ' / TFORM9 = '1E ' / TTYPE10 = 'SLOWTIME' / TUNIT10 = 'none' / TFORM10 = '1E ' / TTYPE11 = 'CLIP ' / TUNIT11 = 'none' / TFORM11 = '1E ' / TTYPE12 = 'THRESH ' / TUNIT12 = 'SECONDS ' / TFORM12 = '1E ' / TTYPE13 = 'SYNTHL ' / TUNIT13 = 'CODE ' / TFORM13 = '1B ' / TTYPE14 = 'OVERL ' / TUNIT14 = 'CODE ' / TFORM14 = '1B ' / TTYPE15 = 'IMODF ' / TUNIT15 = 'CODE ' / TFORM15 = '1B ' / TTYPE16 = 'IFSYNTH ' / TUNIT16 = 'CODE ' / TFORM16 = '1B ' / TTYPE17 = 'TAPEROFF' / TUNIT17 = 'CODE ' / TFORM17 = '1B ' / TTYPE18 = 'RFIEXC ' / TUNIT18 = 'CODE ' / TFORM18 = '1B ' / TTYPE19 = 'CLKSRC ' / TUNIT19 = 'CODE ' / TFORM19 = '1B ' / TTYPE20 = 'IFLO ' / TUNIT20 = 'CODE ' / TFORM20 = '1B ' / TTYPE21 = 'IFSIDE ' / TUNIT21 = 'CODE ' / TFORM21 = '1B ' / MULTMODE= 'SqrCross / Square, Cross, or SqrCross EXTNAME = 'PORT ' / name of this binary table extension END ------------------------------------------------------------------------------- PORT Binary Tables Extension: Data (complete) ------------------------------------------------------------------------------- (This will have to wait until we have actual data!!) -------------------------------------------------------------------------------
Each row of the PORT table describes one complex spectrum produced by the SpectralProcessor. The total number of rows therefore defines the size of the third dimension (CYTPE3 = 'PORT') of the seventh column (TTYPE7 = 'DATA') of the DATA table described below, and the row number provides the index into this dimension.
Each row contains the value of two ports which are identified by BANK and PORT (BANK_A, PORT_A, BANK_B, and PORT_B). For non-cross multiplier mode, i.e., Square, the A and B ports are the same. For example, using two samplers per rack yields:
BANK_A PORT_A BANK_B PORT_B ------ ------ ------ ------ A 1 A 1 A 2 A 2 B 1 B 1 B 2 B 2
For cross multiplier modes, i.e., Cross and SqrCross, the ports will have all combinations. For example, using one sampler per rack yields:
BANK_A PORT_A BANK_B PORT_B ------ ------ ------ ------ A 1 A 1 A 1 B 1 B 1 B 1 B 1 A 1
The MULTMODE keyword specifies whether the scan was intended to be cross and/or squared.
The definitions of the columns in the binary table are as follows: