Content-type: text/html Manpage of uvspect


Section: User Commands (1)
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uvspect - Analyse uvdata spectra and plot amplitude & phase spectra  




uv analysis, plotting  


UVSPECT is a Miriad task to analyse and plot visibility spectra. Plot Amplitude and Phase versus channel, frequency or velocity. The default is to average the selected uvdata for all baselines and polarizations. UVSPECT does not apply the gains, or bandpass corrections when plotting the data.  


The input visibility file. No default.
PGPLOT device (e.g. /retro, plot.plt/im for hardcopy on a Vax, or /sunview, plot/ps for harcopy on a Sun). No default. See documentation on the device keyword for more information.
Averaging interval in minutes. Default is no averaging.
Standard uvdata selection. Default is all visibilities. See documentation on the select keyword for more information.
Line type of the data in the format
Here "type" can be `channel', `wide' or `velocity'. Default is all channels.
Flagging type to plot. Set fmode=a to plot flagged and unflagged data. fmode=u to plot unflagged data, fmode=f to plot flagged data. Default is to plot all data.
fft is a character string describing the FFT processing options. Default fft=' ' does no FFT processing. Other options take the complex FFT for each record and each spectral window before averaging the data.
   +    The sign of the exponent in the FFT.
   -    The sign of the exponent in the FFT.
   s    Add a phase gradient of pi per channel before the FFT
        This produces a half channel shift after the FFT.
   q    Quad swap the input to move the center to the 1st point.
   h    Hanning smooth the output.
Use fft=-qsh to make frequency spectra from HATCREEK correlator lag data with the lsb and usb of LO1 adjacent for each corf. The input uvdata must be the default all spectral channels with the number of channels in each window being a power of 2. Other options to take the FFT of any input line type are possible but not yet implemented.
Hanning smoothing length (an odd integer <15). Is applied after averaging over time. Default is no smoothing (hann=1).
Plot range in the x-direction (in channels or km/s according to the linetype selected). Default is to self-scale.
Plot range for amplitude in the y-direction (in intrinsic units). Default is to self-scale.
Plot range for phase in the y-direction (in degrees). Default is (-180,180) degrees.
Mode can be 'inter' or 'batch'. Default is inter. In either mode, the user is prompted for options after each plot on a non-hardcopy device. The options are applied to the current spectrum, which can then be replotted. mode=inter displays the cursor. Type the first character and <cr> to select option. The cursor handling is network dependent, and the character and <cr> may need to typed several times. Options:
  <cr>   - [Left Mouse]   go to next time average.
  Device - [Middle Mouse] enter new plot device.
  Quit   - [Right Mouse]  exit from task.
  Limits - change plot limits.
  Channel - change x-axis to channel number in the line keyword.
  Velocity - change x-axis to velocity.
  Frequency - change x-axis to frequency.
  Replot - replot current spectrum.
  Position - display cursor position. (if device supports a cursor)
  Write - write out current spectrum to an ascii file.
  End - end of options, get next average.
The original inputs are restored for the next time average.




This document was created by man2html, using the manual pages.
Time: 18:35:39 GMT, July 05, 2011