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difx:vex2difx [2018/09/20 18:07]
cormac [ANTENNA sections]
difx:vex2difx [2021/09/16 22:36] (current)
janwagner [Table]
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 Note, only formal vex files are supported as input to vex2difx.  Similar looking ovex files used at some/all Mark4 correlators are not acceptable, however, with a small amount of work an ovex file can be hand converted to a valid vex file.  It would not be hard to write a conversion script to do this automatically. Note, only formal vex files are supported as input to vex2difx.  Similar looking ovex files used at some/all Mark4 correlators are not acceptable, however, with a small amount of work an ovex file can be hand converted to a valid vex file.  It would not be hard to write a conversion script to do this automatically.
 +
 +===== vex2 support =====
 +
 +On Aug 1, 2021, the vex2 committee completed the definition of vex2.  The final version of the format definition can be found [[https://safe.nrao.edu/wiki/bin/view/VLBA/Vex2doc|here]].
 +
 +difx2fits will be gaining vex2 capability in the [[https://svn.atnf.csiro.au/difx/applications/vex2difx/branches/vex2|vex2]] branch of vex2difx.  A log of supported vex2 features implemented in this branch can be found [[vex2support|here]].
  
 ===== The configuration file ===== ===== The configuration file =====
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   * LBA   * LBA
   * LBAVSOP   * LBAVSOP
 +
 +Note that some work-arounds are needed for complex data to handle limitations of the vex format - see [[complexsamplingvex|this page]] for details.
  
 Some general tips: Some general tips:
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 | toneGuard      | float   | MHz   | 0.125 of bandwidth | When using toneSelection ''smart'' or ''most'' don't select tones within this range of band edge, if possible  | | toneGuard      | float   | MHz   | 0.125 of bandwidth | When using toneSelection ''smart'' or ''most'' don't select tones within this range of band edge, if possible  |
 | toneSelection  | string  |       | ''smart''          | Use an algorithm to choose tones for you.  Read the code to learn more. | | toneSelection  | string  |       | ''smart''          | Use an algorithm to choose tones for you.  Read the code to learn more. |
-| sampling       | string  |       | ''REAL''           | Set to ''COMPLEX'' for complex sampled data or ''COMPLEX_DSB'' for double sideband  |+| sampling       | string  |       | ''REAL''           | Set to ''COMPLEX'' for complex sampled data or ''COMPLEX_DSB'' for double sideband (see also [[complexsamplingvex|this page]]) |
 | fake           | bool    |       | False              | enable a fake data source | | fake           | bool    |       | False              | enable a fake data source |
 | mjdStart       | date    |       | obs. start         | discard any data from this antenna before this time | | mjdStart       | date    |       | obs. start         | discard any data from this antenna before this time |
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 | freqId                | int list  |        | none        | a comma separated list of integers that are freq table indices to select which bands to correlate; default is to correlate all. **Note:** this should be used to select parent bands for zoom frequencies if difx2fits is to be run. **Note2:** freq table indices usable for freqId are found in the .input file FREQ TABLE section  | | freqId                | int list  |        | none        | a comma separated list of integers that are freq table indices to select which bands to correlate; default is to correlate all. **Note:** this should be used to select parent bands for zoom frequencies if difx2fits is to be run. **Note2:** freq table indices usable for freqId are found in the .input file FREQ TABLE section  |
 | phasedArray           | string    |        |             | if specified, tells DiFX to produce a phased array output instead of cross correlations, using the setup specified in this phased array config file                                                                                                                                                                                   | | phasedArray           | string    |        |             | if specified, tells DiFX to produce a phased array output instead of cross correlations, using the setup specified in this phased array config file                                                                                                                                                                                   |
 +| outputBandwidth       | float     | MHz    | none        | if specified, enables DiFX 2.7 outputband mode and auto-determines bands that fit the VEX frequency setups                                                                                                                                                                                                                            |
 +| addOutputBand         | string    |        | none        | if specified, enables DiFX 2.7 outputband mode and adds an explicitly specified outputband, syntax freq@<sky freq low edge MHz>/bw@<bandwidth MHz>                                                                                                                                                                                    |
  
  
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   /data/mk/bx123.003.m5a  54322.766323 54322.812311    /data/mk/bx123.003.m5a  54322.766323 54322.812311 
  
-If times for a file are supplied, the file will be included in the .input file DATA TABLE only if the file time range overlaps with the .input file time range.  If not supplied, the file will be included regardless of the .input file time range, which could incur a large performance problem.+If times for a file are supplied, the file will be included in the .input file DATA TABLE only if the file time range overlaps with the .input file time range.  If not supplied, the file will be included regardless of the .input file time range, which could incur a large performance problem. Start and stop times for a Mark5 or VDIF file can be  
 +extracted using the ''m5bsum -s'' or ''vsum -s'' commands respectively.
  
 A few sample ANTENNA blocks are shown below: A few sample ANTENNA blocks are shown below:
difx/vex2difx.1537430866.txt.gz · Last modified: 2018/09/20 18:07 by cormac