BACKEND
Keywords: pako

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BACKEND

        BACKEND  name      nPart resolution bandwidth fShift
                                 receiverBand [polarization subband|sideband]

        BACKEND  /CLEAR

        Alternative short syntax (only for the backends shown here!):
        BACKEND  BBC   nPart           /REC receiverBand [polarization sideband]
        BACKEND  NBC   nPart           /REC receiverBand [polarization subband]
        BACKEND  4MHz  nPart           /REC receiverBand [polarization subband]
        BACKEND  WILMA nPart           /REC receiverBand [polarization subband]
        BACKEND  FTS   nPart           /REC receiverBand [polarization subband]
        BACKEND  FTS   nPart /FINE     /REC receiverBand [polarization subband]

        Set up backends for heterodyne receivers.

        Character :: name           ! name of backend
        Integer   :: nPart          ! (logical) number of backend part
        Real      :: resolution     ! [MHz]
        Real      :: bandwidth      ! [MHz]
        Real      :: fShift         ! frequency shift [MHz]
        Character :: receiverBand   ! receiver band      to connect to backend part
        Character :: polarization   ! EMIR: polarization to connect to backend part
        Character :: subband        ! EMIR: subband      to connect to backend part
        Character :: sideband       ! EMIR: sideband     to connect to backend part

        Choices for (backend) name are:
        BBC                         ! Broad  Band Continuum Backend
        NBC                         ! Narrow Band Continuum Backend
        4MHz                        ! filter spectrometers with fixed resolution
        WILMA                       ! autocorrelation spectrometers
        FTS                         ! Fourier Transform Spectrometer
        VESPA                       ! autocorrelator with variable resolution

        Choices for receiverBand are (compare RECEIVER command):
        E090 E150 E230 E330 HERA1 HERA2

        Choices for polarization are (for EMIR; compare RECEIVER command):
        Horizontal Vertical

        Choices for subband   |   sideband, when observing with EMIR, are:
                LO LI UI UO   |   LSB USB
        LSB and USB apply only to EMIR bands with 8 GHz bandwidth (E090, E230,
        and E330) and Backend BBC.

        fShift can be used to shift (offset) the backend band within the
        receiver band; this only applies to some backends, in particular
        VESPA. For VESPA, the range for fShift is much smaller than the 4GHz
        subbands of EMIR. For wide-bandwidth backends, fShift is fixed,
        corresponding to the frequency pattern of the EMIR subbands and
        backend bands. See EMIR and backend documentation.

        /CLEAR completely clears the backend setup.

        If option /CLEAR is present, all other parameters and options are ignored.

        NOTE: EMIR subbands, IF cables, and Backends

        The output signals from EMIR are transmitted to the spectrometers and
        NBC through 8 IF cables. Each IF cable carries one subband of bandwidth
        4 GHz. This subbands are LO, LI, UI, or UO.

        NBC, 4MHz, WILMA, and VESPA can only(!) be connected to IF cables 1 to 4.
        FTS parts 1 to 4 can also be connected to IF cables 1 to 4.

        The command options RECEIVER /HORIZONTAL and RECEIVER /VERTICAL allow
        to select up to 4 EMIR subbands that will be transmitted through IF
        cables 1 to 4 (compare HELP RECEIVER /HORIZONTAL and the EMIR user
        documentation). This selection can include Outer subbands.

        In addition, the IF cables 5 to 8 carry the 4 Outer subbands
        corresponding to the subbands selected for IF cables 1 to 4. E.g., if
        we select for IF 1 to 4:
        E230 ver UO    E090 ver UI    E230 hor UI   E090 hor UI
        then the IF cables 5 to 8 will transmit:
        E230 ver UO    E090 ver UO    E230 hor UO   E090 hor UO.

        Only FTS parts 5 to 8 can be connected to IF cables 5 to 8.

        BACKEND NBC|WILMA|FTS /DEFAULT will automatically set the maximum
        number of backend parts for all available subbands.

        BACKEND BBC is completely independant of the sub band selections for
        the IF cables.

        NOTES:
        - for some backends the resolution and/or bandwidth are fixed and the
          short syntax can be used. (The full syntax is supported for all backends).
        - for VESPA always use the full syntax!
        - after changing the receiver configuration: BACKEND /CLEAR is recommended
          followed by the backend setup for the new receivers; without that it is
          possible that pako will not accept BACKEND commands because of unresolved
          conflicts between the RECEIVER and BACKEND setups.
        - However, the backend command will automatically try to disconnect
          backends that were connected to receiver (sub)bands that are not
          connected anymore.

Subsections

- BACKEND BBC
- BACKEND FTS
- BACKEND /DEFAULTS
- BACKEND /CLEAR
- BACKEND /CONNECT
- BACKEND /DISCONNECT
- BACKEND /FINE
- BACKEND /MODE
- BACKEND /LINENAME
- BACKEND /PERCENTAGE
- BACKEND /RECEIVER
- BACKEND EXAMPLES