The software ASTRO can be used to simulate and visualize the receiver/correlator configuration. Astronomers are urged to download the most recent version of GILDAS at http://www.iram.fr/IRAMFR/GILDAShttp://www.iram.fr/IRAMFR/GILDAS to prepare their proposals.
The previous LINE command has been replaced by several new commands (see internal help). The behavior of the LINE command can be changed by the SELECT BURE 1995|2000|2006|2013|2015 command. Default is 2015, equivalent to the new SELECT NOEMA command.
The following ASTRO command will produce a plot of the frequency range covered by WideX and showing the four IF windows of which two must be connected to the narrow-band correlator (an example is shown in Fig. ):
ASTRO\LINE name frequency band [/FIXED_FREQ|/ONGRID]
/FIXED_FREQ: This option can be used to ignore the 500MHz spaced tuning grid
/ONGRID: This option centers the line frequency automatically on the IF tuning grid
The two IF processor inputs for the narrow-band correlator and the setup of the spectral units are selected by the two commands
ASTRO\NARROW Qi Qj /RECEIVER Band_Number ASTRO\SPECTRAL iunit bandwidth fcent /NARROW Narrow_input - [/BAND Mode] - /RECEIVER Band_Number
A session to design the above correlator setup (shown in Fig.) could be:
LINE HCO+-HCN 87.00 LSB 6500 ! Define the receiver tuning. ASTRO displays ! the full 3.6 GHz frequency coverage by WideX. NARROW Q1 Q3 ! Selects the 4.2GHz - 5.2GHz and 6GHz - 7GHz windows ! of the 4-8GHz IF1 band. Polarization is HOR HOR. SPECTRAL 1 160 1020 /NARROW 1 ! Correlator unit #1 covers the [940,1100] IF3 band ! on the first IF input (4.2GHz - 5.2GHz). SPECTRAL 2 20 210 /NARROW 1 ! Correlator unit #2 samples a narrow line centered at ! 210MHz in the IF3 band of the first correlator input. SPECTRAL 3 20 770 /NARROW 1 SPECTRAL 4 160 350 /NARROW 1 SPECTRAL 5 160 475 /NARROW 1 SPECTRAL 6 40 750 /NARROW 2 ! Correlator unit #6 covers the [730,770] IF3 band on ! the second IF input (6GHz - 7GHz). SPECTRAL 7 320 400 /NARROW 2 SPECTRAL 8 320 925 /NARROW 2