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DAS Configuration

The Wiki should document the correct DAS configuration to use for each experiment (click on the “telescope” link next to the config name). There are two DAS configurations commonly used for VLBI at Tid.

This takes two 32 MHz bands and produces four 16 MHz data streams. Data centred at 160 MHz into IFP#1 will be split into two bands: 144→160 MHz and 160→176 MHz. Similarly for IFP#2.

So for example, V209a requires:

  • 2269 - 2285 MHz RCP and 2285 - 2301 MHz RCP for IFP#1 and,
  • 2269 - 2285 MHz LCP and 2285 - 2301 MHz LCP for IFP#2

The frequency setup would be such that RCP in IF#1 would be mixed with a 2nd LO of 445 MHz to put the sky frequency of 2285 MHz RCP at 160 MHz (flipped) and IF#2 would have the LCP signal and the same 2nd LO frequency.

This takes two 16 MHz bands and produces two 16 MHz bands. Data centred at 160 MHz into IFP#1 will be digitised into a single band covering 152 - 168 MHz. Similarly for IFP#2.

This digitises two 64 MHz bands centred at 160 MHz. When loaded into the DAS it will not flip the bands, even though the profile specifically says it should. To flip the band you must do it manually by going to pages 1 and 4 of the setup screens and changing address 30 to 1.

Note that the DAS to VSIB cabling needs adjusting for this mode. See these notes.

lbaops/tidnotes/dasconfig.txt · Last modified: 2015/12/18 16:39 by