CVU file is a CVSD Unfiltered Audio. Continuously Variable Slope Delta modulation (unfiltered) is an alternative handler for CVSD that is unfiltered but can be used with any bit-rate.
Files containing the AMB extension are known as AIMMS Model Files as they refer to the models that the AIMMS (Advanced Integrated Multidimensional Modeling Software) created. The AMB file extension was developed by Paragon Decision Technology and the files with this extension are categorized as data files. The data that these AMB files contain are procedures, identifier declarations as well as core model functions. These files are also based on AIMMS modeling proprietary language wherein these files are saved with the AIMMS project (.PRJ) file it is associated with.