I think D-STAR fans will be interested to note that the Windows/sound-card based Digital Voice programs - WinDRM, DRMDV, FDMDV - have been pulled from distribution. They are no longer available for download. These programs were written by Cesko HB9TLK, and distributed primarily by Jason N1SU through his web site.
The problem is licensing, or lack of it, for the MELP codec that all the programs shared. The codec was developed for the US military and NASA, but was never licensed for free distribution. Several companies share the "IPR" (Intellectual Property Rights) for various forms of MELP. Some of those companies do not permit unlicensed use. MELP was designed for high quality, low data-rate voice communication, and is particularly well suited for HF radio applications. WinDRM occupies about 2.5 kHz of spectrum and sounds like FM with few artifacts when signals are good. Cesko's newest program, FDMDV, used only 1.1 kHz of spectrum. It sounds a little rougher, but still remarkable for that low bandwidth. It works closer to the noise level, and has almost no latency. All the programs use OFDM (multiple carrier) modulation schemes. Some hams have been aware that MELP's legal status was murky at best. Most users probably had no idea. One web site I read said that hams were using a "pirated" copy of the MELP dll. I can't offer a legal opinion, but it appears that use, not just distribution, of the MELP codec violates the IPR license. The AOR digital voice modems use the AMBE 2020 vocoder, and are not affected by the MELP situation. I don't know if any specific legal action or threat precipitated the removal of the Windows programs (not just the codec) from distribution, or if the hams involved just changed their minds on participation. 73, Gary KN4AQ ARVN: Amateur Radio//Video News Gary Pearce KN4AQ 508 Spencer Crest Ct. Cary, NC 27513 <mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] 919-380-9944 www.ARVideoNews.com [Non-text portions of this message have been removed]
