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difx:vex2difx [2019/05/21 16:42]
cormac [Specifying media] |
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. |
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| | ===== vex2 support ===== |
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| | 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]]. |
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| | 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]]. |
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| ===== The configuration file ===== | ===== The configuration file ===== |
| * LBA | * LBA |
| * LBAVSOP | * LBAVSOP |
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| | Note that some work-arounds are needed for complex data to handle limitations of the vex format - see [[complexsamplingvex|this page]] for details. |
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| Some general tips: | Some general tips: |
| | 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 | |
| | 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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