Re:The Fight for Patent-Unencumbered Media Codecs Is Nearly Won
by vvanders on Wednesday January 10, 2018 @01:31PM
(#16117525)
No, that's just the general progression of frequency allocation as we develop better coding and modulation schemes to more effectively use frequency.
On the analog side all new voice specifications on VHF/UHF are mandated to use 12.5kHz instead of the old 25kHz wide channels for the same reasons. Amateur radio is currently the only one I know of that still can use 25kHz wide FM frequencies[1].
P25, DMR, DStar and Fusion all use 12.5kHz since they can get digital audio into much narrower spectrum(DMR in fact supports two channels over one 12.5kHz channel using TMDA which is pretty awesome).
On the analog side all new voice specifications on VHF/UHF are mandated to use 12.5kHz instead of the old 25kHz wide channels for the same reasons. Amateur radio is currently the only one I know of that still can use 25kHz wide FM frequencies[1].
P25, DMR, DStar and Fusion all use 12.5kHz since they can get digital audio into much narrower spectrum(DMR in fact supports two channels over one 12.5kHz channel using TMDA which is pretty awesome).
[1] http://wiki.radioreference.com/index.php/Narrowbanding