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Three choices for the Instrument Setup

With ALMA, a signal can be detected using one of two correlators or with the square-law detector. For a correlator setup one can choose between the bi-lateral/baseline (BL) correlator and the Atacama Compact Array (ACA) correlator. Note however, that within a single SB only one type of correlator can be selected. Hence, once a setup with one type of correlator is added, you are prevented from choosing the other type when adding to that SB.

In the SpectralSpec form, the parameters needed to define a spectral specification and the correlator or the square law detector setup should be filled in. To create the SpectralSpecform select the Instrumental Setup folder in the Resources folder. Via Edit $\rightarrow$ Add Spectral Spec with BL Corr Config , Edit $\rightarrow$ Add Spectral Spec with ACA or Edit $\rightarrow$ Add Spectral Spec with Square law detector you can add one of the two correlator configurations or the square law detector. Alternatively, you can right click and select Add ... from the pop-up menu.

If you wish to use square law detectors together with BL or ACA correlators, i.e. to set up a hybrid mode observation, add a spectral spec with BL correlator configurations (or ACA) and then check the Total power with square law detectors check box in the Spectral Spec panel in the SpectralSpec form editor.

When selecting the newly-created SpectralSpec, the empty spectral specification form is displayed in the Editors pane. First, select either the Forms or the Spectral tab of the Editor pane and make sure to extend the Editors pane or to scroll so that the Spectral Spec and either Correlator Configuration or Square law Setup panels of the SpectralSpec form are completely visible as displayed in Figure  8.9 . If the Spectral tab is selected, the Visual Spectral Editor is enabled (see Chapter  10 ).

Figure 8.9: The panels and fields for the Spectral Spec, Switching and Correlation Configuration. A similar layout exists for the the square-law detector.
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next up previous contents index
Next: SpectralSpec Up: Instrument Setup Previous: Instrument Setup   Contents   Index
The ALMA OT Team, 2011 May 20