Wouldn't it be nice... A world with a Universal Digital Voice Mode capable Radio!

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Call me a dreamer...

Wouldn't it be great if our Flex Radios could handle Icom's D-Star, Yaesu's Fusion, and Motorola's Mototrbo (as well as FreeDV). After all, our silicon is capable of fiddling with all those encoded bits in less than a blink of the eye.

The problem, as I see it, is the proprietary and heavily enshrouded in patents, AMBE vocoder algorithm. But take heart! Unless their expensive lawyers are able to extend their claims any longer, by 2028 it should be perfectly legal to implement this algorithm!

I wouldn't advise anyone to hold their breaths, but a man can dream, can't he?

73,
Roy, AC2GS
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Roy Laufer

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Posted 4 years ago

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Neal - K3NC, Elmer

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You can be a dreamer but Flex has added the capability for a developer to write these modes if they want to spend their time and money (and avoid licensing issues from proprietary software). They showed a demo of FreeDV at the ARRL digital conference written using their software hooks. This allows developers to write software that will run in the radio as opposed to just on the customer PC.

Its not dreaming, I predict someone this year will do something to prove it (maybe like porting MMTTY to run inside the radio, etc.).
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Roy Laufer

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I agree and very much hope you are right!

The problem with all the commercial Digital Voice Modes are that the companies that say that they are open source are disingenuous - they all use a highly proprietary and hawkishly guarded AMBE vocoder algorithm. If anyone takes the necessary time and effort to implement that algorithm for us I will bet you the people that own AMBE's patents will hunt him down and shut him down. I know of no one who would be willing to work so hard to get drowned in "cease and desist" orders and court warrants for theft of intellectual property.

I would be interested in finding out how Connect Systems will be getting away with an all protocol digital voice $250 HT that uses this technology. I hope/assume (for their sake) they have bumped their cost for this Chinese design due to the additional tribute to AMBE's owners.

Roy
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Steve W6SDM

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I guess my question for digital voice is, do we really want it?  I have a Yaesu FTM400DR for my mobile rig. We are starting to see the Yaesu repeaters spring up in the Phoenix area.  When the signal is good, it's good - a little nasal on the narrow mode but still good.  However, when you start to lose the signal, it's unintelligible.  Missing a few packets out of a voice message can really make it unreadable.

Regarding the patents, yeah, I share your dream.  Off topic but, if we can get pharmaceutical companies to cooperate when their patent is up so that generic drugs can be available for the benefit of mankind, that would be an amazing thing.
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Lee - N2LEE

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While I support the advancement of digital voice technology, if I were on the Flex development team, digital audio would be way down the list of features that need to be implemented.

Seems to me the road map they have released is the right set of priorities.
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N7AIG

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Something I have been wondering about is QRM mitigation with DV. Why not implement a version using CDMA. As I understand that term, it refers to modulation of different channels, all occupying the same frequency space, with a long orthogonal binary polynomial code, so that overlapping channels in frequency still retain their separate identities. Someone more familiar with this should jump in and correct my misunderstandings...

73 de Dave, N7AIG

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k3Tim

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Dave - You are correct.  CDMA is a wide band (WB) signal that uses a code to convert the narrow band (NB) signal to a WB.   The transmitted signal is spread spectrum.  The code words are orthogonal to each other so the NB signals never interfere with each other.  

Two hurdles:

The code word would have to be assigned to a station and then released.  This should be do-able for our use case.

The CDMA base station controls the output power of each device hundreds of times a second.  This aspect of CDMA is totally amazing to me!  The base makes sure all mobiles are received at the same signal strength at the base.  It doesn't want one to swamp out the others and cause interference.  Not sure how this fits our use case.

The received signal strength is also measured at the mobile (MSM) to a tenth of a dB or better, aka. accurate S-meter!
 
Best Regards,
TimP / k3Tim
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Robert -- N5IKD, Elmer

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The FreeDV solution is already available to all radios via either free software, or the soon to be available microphone that you can purchase.

Our Flex 6000's have the ability to add our own protocols that we can build and also share with the world.
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Lee - N2LEE

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Robert, I was wondering the same thing and why the integration was necessary. Is there any reason why FreeDV can't be setup like any other digital mode using DAX ?
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Robert -- N5IKD, Elmer

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I use FreeDV now using DAX like any other digital mode. It works great. The primary advantage to putting it in the radio that I see to access FreeDV from other computers without having to install FreeDV at each station.

Also if it is available with a simple button click it is more likely be used and the more it is used the more useful it becomes. We are seeing the chicken and egg scenario unfolding before our mics.