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Next: STATE Binary Table Extension Up: gbtSPFits Previous: Primary HDU keywords

PORT Binary Table Extension

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:

BANK_A
Identifier for the first bank containing the A/D sampler for the spectrum.
PORT_A
Index to the A/D sampler in BANK_A for the spectrum.
BANK_B
Identifier for the second bank containing the A/D sampler for the spectrum. This will be identical to BANK_A in Square mode.
PORT_B
Index to the A/D sampler in BANK_B for the spectrum. This will be identical to PORT_A in Square mode.
TAPER
Describes the weighting function used on the A/D amplitude-vs-time series before its transformation. Possible values are Box, Halfbox, and Cosine.
FREQRES
Specifies the frequency resolution, i.e., Hz per channel.
BANDWDTH
Specifies the port bandwidth.
ATTENUAT
Specifies the port attenuator setting.
FASTTIME
Specifies the response time of the total power pulsed RFI threshold detector.
SLOWTIME
Specifies the response time of the baseline comparison level for the total power pulsed RFI threshold detector.
CLIP
Specifies the maximum instantaneously level applied to the slow baseline integrator. It is specified in fraction of the total IF power plus noise peak level with the given bandwidth.
THRESH
Specifies the level difference between the outputs of the fast and slow integrators that will flag an RFI pulse. Specified in fraction of total IF peak noise excursions from the average DC detected level with the given bandwidth.
SYNTHL
Designates whether the IF's synthesizer is out of lock, i.e., 1 if out of lock.
OVERL
Designates whether the total power is overloaded, i.e., 1 if overloaded.
IMODF
Designates whether the InterMode filter is is, i.e., 1 if in.
IFSYNTH
Designates whether synthesizer doubler is on, i.e., 1 if doubling.
TAPEROFF
Designates whether synthesizer taper offset between racks is on.
RFIEXC
Designates whether RFI excision is on.
CLKSRC
Designates whether closck source is external, i.e., 1 if external.
IFLO
Designates whether the IF's LO is external, i.e., 1 if external.
IFSIDE
Designates whether the IF's sideband selection if upper or lower, i.e., 1 if lower.


next up previous
Next: STATE Binary Table Extension Up: gbtSPFits Previous: Primary HDU keywords
Bob Garwood
2011-07-25