## Intensity array

The intensity array (RY) is extracted from one or more columns in the binary table. There are 2 possibilities:

- the flux_* columns (where * is the subband number), each of them producing a different spectrum (level 2.0). In this case, one row of the column contains all the channel values. The associated frequency array is found in the column lsbfrequency_* or usbfrequency_*, else an error is raised.
- the flux column, producing a single spectrum (level 2.5). In this case one row of the column contains 1 channel value. The associated frequency array is found in the column frequency if available, else wave, else an error is raised.

All spectra (flux and frequency arrays) are always sorted in ascending frequency (if needed), before setting the spectroscopic section as described in the Table . The Not-a-Number (NaN) values (if any) in the flux array are patched to the bad value defined in the CLASS header.