Keywords: class

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## Miscellaneous

- `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