General Set-up File

  As discussed in Section 4.2.2, the general set-up file customizes the system environment for your project, and in particular points to YOUR source list, log-file, procedures file, and correlator setup file. In addition it invokes your receiver, invokes the IF/LO setup, and sets the frequencies you want to observe in each of the four independent sub-correlators. It may also place front-end filters into your signal path, and change the default size of the gain cal. In this appendix, we both describe generic set-up and correlator files, and present the "standard" set-up files (.sls files) which are available through the AO Control Observer GUI.

The project number for these files is a9999. The gui-generated files are therefore called a9999.sls, the source list is src.list, and the log file is a9999.log.

Contents of general set-up file:

#goto your project directory
cd /share/obs4/usr/a9999	;

#open a log file for your session.  All of your observation logs will be placed
#here.  you may wish to change this name day by day (i.e. a9999.05may.log, 
#a9999.06may.log).
logOpen       a9999.log         ;

#attach your source list for the session
srcfile       src.list          ;

# Source the standard procedure which is invoked as 'dosrc'
# The file chosen here depends on which procedure you wish to run
# (i.e. onoff.tcl, hex.tcl, etc.).
source /share/obs4/usr/a9999/#procedure#.tcl

# Set correlator board and mean RF center frequencies.
# These can then be shifted to account for velocity.
set sbfr1 #sbfr1#
set sbfr2 #sbfr2#
set sbfr3 #sbfr3#
set sbfr4 #sbfr4#
set rfcfr #rfcfr#

# Setup Doppler corrections.  The velocity 'type' can be chosen to be
# hel, topo, LSR, or geoc, and you can list your velocities as v, z(optical),
# or z(radio).  Additionally, you can either doppler correct based on the
center frequency of your bands (rfonly), or doppler shift the center of each
# band (sball).
dopsetfrq $rfcfr $sbfr1 $sbfr2 $sbfr3 $sbfr4
dopsetvel 0 #vel_type#
dopset#sball or rfonly#
dopsetdoit

# Set cal to hcal (preferred) or lcal
setcal #cal#

# Assert VLBI tone cal off
acvlbical off

# Adjust IF power levels
adjpwrif1
adjpwrif2 -e 3

# Correlator setup parameters start here

# What are these?
calport 1
corcal 0

# No of sec. to wait between datataking. May be set to 60s, 10s or 1s
set estart #enum#

# No. of cycles at 50MHz.
set dumplength #num#

# Sets sampling level in each sbc
set lagsam "#ls1# #ls2# #ls3# #ls4#" 

# No of lags (chans) for each sbc
set lags "#lg1# #lg2# #lg3# #lg4#"

# No of cycles for each integration, 1 cycle = 1 sec
set icyc #no. cycles#

# Bandwidth code for each sbc.
set bandwd "#bw1# #bw2# #bw3# #bw4#"

Correlator boards used. Can be any combination of boards 6, 7, 8 & 9
set corbrds "#bd1# #bd2# #bd3# #bd4#"

# Define master control program.  The next series of lines is described more
# fully below.

mcp setup corProg@cor "
cor_lagc $lagsam	;# Sampling for each correlator
cor_dblnyquist f	;# Sets sampling type to double-Nyquist
cor_bwnum $bandwd	;# sbc bandwidth definition
cor_lagspersbc $lags	;# Define no. of lags/sb
cor_extstart $estart	;# No of sec to wait between datataking?
cor_adjpwr FALSE	;# Adjust power each time data is taken?
cor_dmplen $dumplength	;# Sets the interval between data dumps in seconds
cor_chiptestmode FALSE	;#Used for testing the chips.  You always want it to be FALSE
cor_dmpsperinteg $icyc	;#Number of cycles per integration
cor_dataformat 3 3 3 3	;#Data format. 3=FFT, used for spectral lines
cor_rdpowcntr TRUE	;#Reads power in 50MHz range
cor_relbitshift 0	;#Bit shift cor the correlator (you want this to be 0)
cor_rdtotcnts FALSE	;#If TRUE, read 1025th channel in sbc (you want this to be FALSE)
cor_enablanking FALSE	;#No software in place for this, so leave it FALSE
cor_brdlist $corbrds"	;#Correlator boards used, plus final " to end mcp program.

#Turn computer disc on for writing
disc on

#adjust power levels to the subcorrelators
cor "cor_adjpwr false cor_rdp t"

# END of spectral line setup file: a9999.sls

In the following paragraphs the commands invoked by the master control program will be described. The first line of the set invokes the master control program. This is followed by a series of lines concerned with the correlator.

1. "mcp setup corProg@cor "": This line is executed before any observing commences. It provides the master control program (mcp) with the instructions to execute the subsequent lines.
2. The next set of lines deal directly with the correlator setup. The correlator is composed of four independent boards, each a full correlator in its own right. One such board can observe both polarizations, or just one of the two on offer, at a bandwidth and resolution that is set independently for each board. The signal may be three-level, three-level interleaved, complex, three-level stokes, or nine-level sampled. At bandwidths of 12.5 MHz or less, the S/N from three-level spectra can be improved by oversampling (using double-Nyquist sampling). The possible settings, as well as the maximum bandwidth per sub-correlator, number of sub-correlators for each polarization, number of channels per sub-correlator, etc. can be found in Table 2.3.1 and is implemented as follows:
   1. "cor_lagc $lagsam": Sets sampling for each correlator according to Table 2.3.1
   2. "cor_dblnyquist f": Can be set to "t" or "f" to invoke (or not) double Nyquist sampling
   3. "cor_bwnum $bandwd": Sets the bandwidth of each sub-correlator according to bandwd = n, where n is bw = MHz. At present n can go from 1 to n (bandwidths of 50 - 0.195 MHz).
   4. "cor_lagspersbc $lags": Sets the number of labs for each sub correlator. Can be set to 1024, 2048, or 4096 based on the limits set by the sampling and given in Table 2.3.1.

3. "cor_extstart" sets the number of seconds to wait between data taking to ensure the telescope in in position. Currently a setting of "10" works fine.
4. "cor_dumplen" Sets the number of cycles at 50MHz. That is, if num=50000000 there is 1 dump per second. If num=5000000 there is 1 dump every 0.1 sec.
5. "cor_dmpsperinteg" Determines the number of cycles (whose length is set by cor_dumplen) per data dump. I.e. if cor_dumplen is set to 50000000 and cor_dmpsperinteg is set to 60 you will get 60s data dumps.

The followingfiles are available through the "standard files" button on the AP Observer's gui, and are described in the next subsections.

• file 1: Known Velocity with L-narrow bandwidths of 12.5 & 6.25 MHz/sbc (sbc = sub-correlators) (2600 km/sec coverage) Can be readily modified for the L-wide receiver (a9999a.sls)
• file 2: Velocity Search with L-narrow bandwidth 25 MHz/sbc giving frequency coverage of 1370 to 1432.5 12.5 MHz (-2,500 to +11,000 km/s coverage with a resolution of 5.2 km/s) (a9999b.sls)
• file 3: Velocity Search with L-wide - moderate bandwidth 25 MHz/sbc frequency coverage of 1337.5 to 1422.5 MHz (-400 to +18,500 km/s coverage with a resolution of 5.2 km/s) (a9999c.sls)
• file 4: Velocity Search with L-wide - extreme bandwidth 50 MHz/sbc 3-level interleaved sampling, 4 sbcs/polarization, 2048 lags/sbc frequency coverage of 1237.5 to 1422.5 MHz (-400 to +44,250 km/s coverage with a resolution of 5.2 km/s) (a9999d.sls)

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