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- DIVIDE makes the ratio of the R and T spectra. The two spectra
must have the same velocity scale.
- FFT plots the power spectrum of the current observation. It
might help identify spurious ripples. Editing of the fourier transform is
possible, so that these ripples may be suppressed.
- NOISE generates a Gaussian noise as intense as in the current
spectrum using the rms value determined by the BASE command, or
using a rms value given as an argument. NOISE Value NEW will create
a noisy spectrum of given noise level into R, after copying R in T.
- RESAMPLE resamples the R spectrum on the specified grid. If the
final sampling is coarser than the original one, a smoothing occurs to
the final sampling.
- SMOOTH operates a Hanning smoothing by default and divide the
number of channels by two. Other arguments can be specified to use other
methods. SMOOTH AUTO uses a sophisticated variable-resolution
algorithm, but it requires the channels to be really independent and this
is apparently seldom the case in radio astronomy. SMOOTH GAUSS
Width convolves the spectrum by Gaussian of given Width in current
units; it does not take care of bad channels. SMOOTH BOX N make
the average of N adjacent channels and divides the number of channels by
N.
Next: Continuum and Skydip Processing
Up: Spectra Line Processing
Previous: Gridding Spectra on a
Contents
Index
Gildas manager
2014-07-01