## Data not available / bad channels

Equations and describe the general case when all the input channels which contribute to the output sum are available. Nevertheless there may be some situations were data is missing. In such cases, the general rule is to ignore the channels with no data (i.e. zero-weight them in eqs. /), and to use data in the other spectra when it is available:

- In the COMPOSITE mode, if no data is available in an input spectrum (i.e. out of its boundaries, in a frequency range covered by other input spectra), its corresponding resampled channels are zero-weighted.
- In the COMPOSITE mode, if no data is available in all the input spectra (e.g. there is a gap covered by none of these), the corresponding channels in the output spectrum are flagged as bad.
- In all modes, any bad channel in an input spectrum is zero-weighted. Additionally, if it contributes to the output channel () but bad channels should propagate (SET BAD OR), it contaminates the current output channel which is also set as bad.