SPD - Spectra Display for ATNF Correlators

Description

SPD displays data from the correlator, either in the lag domain - the correlation function as measured directly by the correlator, or in the frequency domain - the spectrum which results from the Fourier transform of the correlation function. The user can select which of the products contained within the correlator configuration to display and in what form to display them.

SPD can also display the bin profile for correlator configurations which provide time or pulsar binning.

Note:
Versions after 26 Sep 2002: For the correlation function, the default action is to display only that part of the function which is actually measured in the correlator. For autocorrelations, this will generally be only be the positive lags. If negative lags are requested with the 'lags' command, for autocorrelations, the positive lag measurements are mirrored into the negative lags for display.
Versions before 26 Sep 2002: The correlation function is always shown for both positive and negative lags. If only positive lags are measured, as is normally the case in an autocorrelation function, the positive lag measurements are mirrored into the negative lags.

Commands

Type the following commands - minimum match - in response to the prompt >

>mode

Defines the mode in which the select command operates in selecting products to display. 
>mode v	   - selection by variable or product number.
>mode b	   - selection by baseline/polarisation.

>select

Selects which products to display.

1. Selection by product number ( mode v ):

In the following examples, the letters refer to the type of display. viz. The numbers refer to the product numbers in the order they appear in the correlator configuration.

Examples: 
>select l1 a1  	   - displays lag and frequency spectra of product 1 on separate plot panels.
[For versions before 27 Oct 2000]
>select a1+2  	   - displays frequency spectrum of products 1 & 2 on one plot panel.
>select a1+2 a3+4  - displays frequency spectra in two panels, each containing two products.
[For versions after 27 Oct 2000]
>select a1&2  	   - displays frequency spectrum of products 1 & 2 on one plot panel.
>select a1&2 a3&4  - displays frequency spectra in two panels, each containing two products.
>select a2-1       - displays the difference frequency spectrum between two products.
>select 1-2 4+5    - displays difference and sum frequency spectra in two panels, using the 
                     global display type (see below).
Special Multibeam Selection: 
>select mbN  	   - displays lag or frequency spectra of N beams, two polarisations per 
                     plot panel, in the multibeam layout.
2. Selection by baseline/polarisation ( mode b ):

A new plot panel is created for each baseline and frequency selected.

Examples: 
>select 1aa  	   - displays all baselines with antenna 1, polarisation AA, frequency 1.
>select 12ba  	   - displays baseline 1*2, polarisation BA, frequency 1.
>select 14cc  	   - displays baseline 1*4, polarisation AA, frequency 2.
>select cd	   - displays all baselines, polarisation AB, frequency 2.
>select 24	   - displays baseline 2*4, all polarisations.
Note: The polarisation types must be enabled with the ON/OFF command - see below. Initially only AA, BB, CC and DD are enabled.

Then use one of the global display type commands to select the display type. 

>select bp11	   - displays the bin profiles for baseline 1*1, all polarisations.
>select pp11	   - equivalent to above.

The bin profile plots the integrated amplitude spectrum against bin number. The limits of the integration, by default the entire spectrum, can be defined by the channels command.

>l or >a or >p or >d or >r or >i

Sets the global display type and changes all current panels to this display type.

>x

For frequency domain plots, toggles the X axis units between frequency and channel number.

>array

In baseline mode, defines the currently active antennas.
Examples: 
>array 1346	 - antenna 1,3,4,6 active, antennas 2,5 inactive.
>array		 - print out the currently active antennas.

>bins

In baseline mode, and when time or pulsar binning is active, defines the currently selected time bins.
Examples: 
>bins 1-5 10-16	     - selects bins 1 to 5 for frequency one, 10 to 16 for frequency 2.
>bins 1.3.5 10.11    - selects bins 1,3 & 5 for frequency one, 10 & 11 for frequency 2.
>bins 		     - print out currently selected bins.

>on OR >off

In baseline mode, defines which polarisations are enabled.
Examples: 
>on ab ba cd dc      - turn on display of all cross polarisation products.
>off cc cd dc dd     - turn off all second frequency polarisation products.
>on                  - display which types are currently on.
In baseline mode, when operating with the LBA Correlator, defines which product types are included in the selection process. In the LBA Correlator there are four product types. The SIN and COS products are actually formed in the correlator, whilst the SSB1(+) and SSB2(-) products are formed from a phased combination of the SIN and COS products. The SSB1(+) products form the final data which are archived. The SSB2(-) products should contain only noise. Note that the SSB products exist only in the frequency domain. A correlation function display of these products is not possible.
Examples: 
>on sc      - turn on display of both SIN and COS products.
>on sc+-    - turn on display of all types.
>off sc-    - turn off all but the SSB1(+) products.
>off        - display which types are currently off.

>scale

Allows the plots to be scaled on the Y axis. The default is auto-scaling.
Examples: 
>scale l -0.01 0.01	 - scale lag plots to cover the range -0.01 to 0.01
>scale b 0 200		 - scale bin profile plots to cover the range 0 to 200
>scale a		 - return to auto-scaling for amplitude plots.
>scale			 - autoscale all plots.

>channels

Allows a selection of a range of frequency channels to plot. The default is all channels.
Examples: 
>channels [f1] 100 200	    - display channel range 100 to 200 for frequency band 1.
>channels f2 200 500	    - display channel range 200 to 500 for frequency band 2.
>channels 100 200 300 500   - display channel range 100 to 200 for frequency band 1  AND
                                      channel range 300 to 500 for frequency band 2.  
>channels		    - reset channel selections to defaults.

>lags

Allows a selection of a range of lag channels to plot. The default is all channels.
Examples: 
>lags [f1] -800 100	    - display lag channel range -800 to 100 for frequency band 1.
>lags f2 -100 500	    - display lag channel range -100 to 500 for frequency band 2.
>lags -200 200 -100 100	    - display lag channel range -200 to 200 for frequency band 1  AND
                                      lag channel range -100 to 100 for frequency band 2  
>lags		            - reset lag channel selections to default.

>bpbins OR >ppbins

In baseline mode, and when time or pulsar binning is active, defines the range of bins over which the bin profile is plotted.
Examples: 
>bpbins 20 30	     - displays the bin profile for bins 20 to 30.
>ppbins		     - reset to the full range of available bins.

>avg

When the next data arrives, resets the averaging buffers and starts a vector averaging in time of the frequency spectra. This also results in a time averaging of the bin profile.

>noavg

When the next data arrives, reverts to non-averaging mode.

>save

Saves the current frequency spectra in a stored reference area.

>auto

Enables an automatic averaging mode where the averaging is reset at the start of each scan. If the scan is on a reference position then the averaged data will be saved in the reference area and subsequent signal scans will be displayed as quotient spectra.

>noauto

Disable automatic averaging mode.

>layout

Controls the layout of plot panels. The default layout is the smallest square (NxN) layout which will contain the number of plot panels, with the exception that a two panel layout defaults to 1x2, representing :
(number of panels in X) x (number of panels in Y).
Examples: 
>layout 3x4	    - 3 panels in X by 4 panels in Y.
>layout 0x0	    - revert to default layout.
>layout		    - prints out current layout.

>write [colour] [filename]

Writes a [colour] postscript file of the current display to the filename, if given, otherwise to a constructed filename which includes date and time. The path used is the environment variable SPD_HARDCOPY, if defined, otherwise the directory from which SPD was started. A message is printed identifying the actual filename used.

>quit

Exits the program.
Last updated: Warwick Wilson 27 September 2002

wwilson@atnf.csiro.au