NAME:
sp_dedisp1 - dedisperse a buffer of wapp data.
SYNTAX: sp_dedisp1,spc,f1,df,dm,timeSmp,smpOff,dedisp,refRf=refRf
ARGS:
spc[nchn,nspcSmp,nsmp]:float Spectra to dedisperse. If 2 dimensions then
assume just 1 spectra per sample
f1 :double center frequency of first channel (Mhz).
df :double Channel width (Mhz). The sign tells whether spc[*,]
is increasing frequency (unflipped) or decreasing
frequency (flipped).
dm : double dispersion measure
tmSmp:double time between samples (secs)
smpOff :long The sample number that spc starts at. This is for use when
the routine is called multiple times
KEYWORDS:
refRf:double reference frequency to use for dedispersion. The default
is the first bin of each band.
RETURNS:
shiftAr[nchans]:long shift values for each channel.
dedispA[n,nspcSmp]:float the deddisped time series by spectra persample
The dedisp should be allocated to hold the max number of samples +
the maxium sample delay across the band
DESCRIPTION:
Dedisperse one input buffer of spectra (usually from pdev). f1,df,dm,
timeSmp and optionally refRf determine how to dedisperse spc. f1 is the frequency of
the first channel of the spectra. df should be set to the channel spacing (negative
if the frequency decreases across the band).
You can use refRf to dedisperse relative to refRf (rather than f1).
The dedispersed data is returned in dedisp[nsmp,Nspc]. You should
dimension dedisp large enough to hold all of the dedispered data
for however many calls you will make to sp_dedisp1. smpOff points
to the offset in dedisp where the first time sample of spc goes. The
code checks the indices so that all dedispersed power before smpOff=0
is thrown into smpOff=0. You need to dimension dedisp to hold any
extra data at the end of the last time sample (from freq channels
below the reference frequency).
to keep the timing straight, f1 or refRf should be the highest
frequency. Then the first sample returned will have the first sample of
refRf.
This routine is normally calledl by sp_dedisp(). for pdev it is called
by itself.
NOTES:
spc[ii]+=spc[jj] where len(i) = len(jj)
it's ok if some of ii or jj repeat.
SEE ALSO:
sp_dedsip,sp_dmdelay,sp_dmshift
NOTES: this code was borrowed from duncan lorimer's sigproc routines.
HISTORY:
26MAY06:- changed arguments dedispA,dedispB to deDisp[nsmp,Nspc] to allow
for alfa data when you have multiple beams coming back from
1 board (1,2, or 4).
(See /pkg/rsi/local/libao/phil/pulsar/sp_dedisp1.pro)
NAME: sp_dmdelay - delay in secs between two sky freq SYNTAX: delay=sp_dmdelay(f1,f2,dm) ARGS: f1: double frequency 1 Mhz f2: double frequency 2 Mhz DM: double dispersion measure RETURNS: delay:double in seconds DESCRIPTION: Compute the delay f2-f1 for dispersion measure dm. Positive numbers means that f1 arrives after f2 (f1 is the lower freq) NOTES: I stole this from dunc's sigproc routine
(See /pkg/rsi/local/libao/phil/pulsar/sp_dmdelay.pro)
NAME:
sp_dmshift - compute the shift values for dedispersion.
SYNTAX: shiftAr=sp_dmshift(f1,df,nchans,dm,tmSample,refRf=refRf,
nbands=nbands)
ARGS:
f1 :double center frequency of first channel (Mhz).
df :double Channel width (Mhz)
nchans:int total number of channels
dm : double dispersion measure
tmSample: double time samples (secs)
KEYWORDS:
refRf:double reference frequency to use for dedispersion. The default
is the first bin of each band.
nbands:long number of dedispersed bands to return. default=1
nbands must divided evenly into nchans
RETURNS:
shiftAr[nchans]:long shift values for each channel.
DESCRIPTION:
Compute the shift values for each frequency channel to use when
dedispersing a time series.
NOTES:
Stole from dunc's sigproc routine.
(See /pkg/rsi/local/libao/phil/pulsar/sp_dmshift.pro)
NAME:
tempoget - read a polyco file
SYNTAX: n=tempo_getdata(polycoName,polyI)
ARGS:
polycoName: string polyco.dat file to read (created by tempo)
RETURNS:
n: int >=0 number of entries found in file
-1 can't open file
polyI[n]: struct holding info read from file
(See /pkg/rsi/local/libao/phil/pulsar/tempo_getdata.pro)
NAME:
tempo_comp - compute pulse phase and freq from polyco.dat
SYNTAX: istat=tempocomp(mjd,polyI,retI)
ARGS:
Mjd: double time of interest
polyI: {} polyco.dat info from tempoget
RETURNS:
istat: int status of computation
0 ok
< 0 error
-1 requested tmmjd comes before polyI times
-2 requested tmmjd comes after end of polyI times
retI: {} strucuture holding return info
(See /pkg/rsi/local/libao/phil/pulsar/tempo_comp.pro)