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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.
lucas@iram.fr