Changes between Version 60 and Version 61 of Changes/atlod

Timestamp:

12/20/07 09:42:49 (16 years ago)

Author:

MarkWieringa

Comment:

--

Changes/atlod

@@ -3 +3 @@
  ||atlod                     ||            ||          ||           ||      ||
  ||Item                      || Complexity || Research || [milestone: Milestone] || Time ||
- ||[wiki:Changes/atlod#SYSCALRecordChanges Sampler Statistics]         || easy       || none     || 7 || 1d ||
+ ||~~[wiki:Changes/atlod#SYSCALRecordChanges Sampler Statistics] ~~        || easy       || none     || 7 || 1d ||
  ||[wiki:Changes/atlod#SYSCALRecordChanges Storage Of SYSCAL Data]       || moderate   || some     || old6 || 2*5d||
  ||ApplyingXYPhaseCorrections|| easy       || little   || old6 || 5d ||
@@ -49 +49 @@
 == Data Size Limits ==
  Research needed: check for size limits on the data dimensions - number of windows, channels, etc
+   * Limit on number of channels is ok, edit maxchan in maxdim.h. The total number of simultaneous channels from CABB could be as high as 74k. The main limits on CABB output rates are set by the maximum rate data can be written to disk, so we need to wait to see what will be used in practice. Currently maxchan is set to about 32k.
+   * Limit on number of spectral windows or if_chains is set by max_if=16 in rpfits.inc. This should be ok for most observations, but CABB could produce up to 34 simultaneous spectra (2 continuum bands with up to 16 zoom bands each). The constant ATIF in atlod.h sets the maximum number of IFs atlod can cope with, it has been increased from 4 to 16 to match the rpfits limit.
 
 == Identify Parent Window ==
@@ -55 +57 @@
 
  Research needed: Determine whether it is necessary to keep track of the children of a particular band.
+   * We can use the if_chain variable to keep track of this, all zoom bands should have the same value for if_chain as the main continuum band. Comparing the if_chain and the time stamps for the data is sufficient to identify the parent window.
 
 == Flagging Within ATLOD ==
@@ -67 +70 @@
  Research needed
  * What are the birdie frequencies in the new system?
+    * There may be birdies and there will definitely be known external RFI that can be masked out.
  * Can data be flagged automatically by ATLOD using [Glossary/AutoCorrelations autocorrelations]?
    (Could we use algorithms from 'pieflag'?)
+    * Probably not - it's hard to distinguish genuine spectral lines from RFI, it might be possible for continuum observations.
 
 == More Selection Options ==
@@ -76 +81 @@
  MarkCalabretta wrote the 'rpfhdr' utility which does most of this.
 
+ * rpfhdr will give you the frequency table for each scan, atlod followed by uvindex gives a detailed listing of the frequency setups present.
+ * the ifsel selection in atlod lets you select the cabb continuum bands 1 or 2 for loading. At present there is no way to just load a single zoom band.
+
  Research needed: How are zoom bands to be represented in the RPFITS data format?
+
+ * Just like current multiple simultaneous IFs, except that the if_chain number is set to that of the parent continuum band.