--- In [email protected], "John D. Hays" <j...@...> wrote: > D-STAR by definition includes AMBE, any other vocoder is not D-STAR.
OK, but there's nothing wrong with extending the current protocol and calling it D*Star+ or just "D*Star Compatible" or whatever. > (If it doesn't infringe on someone else's intellectual property -- which > means it better get patented or otherwise protected so someone else > doesn't patent it after the fact -- big dollars.) If it's been disclosed publicly (prior art), in theory it can't be patented "after the fact." ...although I realize these days it's par for the course for many companies to patent any and everything they can think of, since even when it's clear there is prior art, the patent holder can claim ignorance and since it's essentially impossible to prove what the patent holder did or didn't know (and when), worst case the patent holder loses the license -- making them no worse off than if they hadn't filed in the first place. That being said, the AMBE codec in particular likely does have some "real" (non-obvious -- at the time -- to those skilled in the art, etc.) novelty/invention that's worthy of patent protection. > I think cost is a red herring -- the AMBE chip is around US$20+ per > unit. If the new vocoder can be produced for that price in small > quantities for hams it would be very surprising. I agree with you there, although in actuality the price between a D*Star radio and an otherwise equivalent non-D*Star radio is more like $100-$200. But still, for most hams, that shouldn't be a significant impediment and a freely available CODEC isn't likely to sell noticeably more radios. (I think he's intending for CODEC2 to be implemented in "whatever processor you already have around" in your PC or radio anyway, though, so the cost is effectively free. The AMBE chip is just a pre-programmed TI DSP, after all, and pretty much any contemporary PC has plenty of CPU cycles around to implement the algorithm; it's in the form of a chip so that it isn't just pirated rampantly.) Heck, there are already some freely available CODECs out there anyway that seem to perform pretty well (although weren't specifically designed for wireless usage): Speex and the Skype-CODEC come to mind. (I'm not up on the specific licenses, however -- they're "free as in beer" at least, though.) One thing to keep in mind is that, since most hams operate D*Star through repeaters anyway, one approach here would be to have the *repeater* have both AMBE and CODEC2 (or whatever) capabilities, and just translate between them on-the-fly. (This approach is used with public service radio systems, since there lots of different companies decided to build their own proprietary protocols and used different CODECs as well.) I would wager that repeater usage probably accounts for more than 90% of D*Star voice traffic, and getting repeater builders to incorporate a backwards compatible radio into their system (that has the same interface as the current Icom boxes) is nowhere near as daunting as getting everyone with an HT or mobile D*Star rig to buy something new. ---Joel KE7CDV
