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Comment Re:MOS? (Score 1) 37

You could do this using FRS walkie talkies, as long as they have microphone and earphone connections. Or analog telephones. It's been tested multiple times on ham FM walkie talkies. Anything that carries voice should work. The bandwidth is only 1.25 kHz and I think the low end starts at about 700 Hz.

Comment Re:MOS? (Score 1) 37

There is a video of the codec vs. SSB on the same radio link here. You can also take any radio links you have at hand and run the FreeDV program. This is an evening project to set up without a business case, and at least some companies appreciate people who take the initiative to do this sort of thing.

Comment Re:1200 bits/s, not bauds. (Score 1) 37

Sorry. When I say "1200 Baud", I am in general thinking of the TAPR TNC 2, which was never built for voice but can do it, to a degree, with this codec. It's sort of a Bell 212 modem on half-duplex radio. There were many commercial products based on the TNC 2 design and many hams have them on hand. It's a good demo to put speech through a pair of them, not really practical because the latency is high.

Comment Re:MOS? (Score 1) 37

MOS is only for people who want to pay a lot of money. Of the automated processes, the one available to us isn't validated for less than 4K bps codecs.

It would be a great improvement to MOS if there was an open version of POQLA. But the actual customer base for the codec have never even heard of MOS and thus we aren't volunteering to write that. The folks who want to put it in expensive government support systems yet aren't willing to help with testing don't get our sympathy.

Comment Re:Code2 voice sample @4:50 (Score 1) 37

We avoid some techniques that would make the noise performance worse. The HF version of the codec doesn't vector quantitize, and doesn't do any delta coding between frames. The current FEC is Golay and we are investigating low-density parity codes.

There is a lot yet unheard about the Ratheon codec, regarding its actual noise performance and how well the listener can distinguish different speakers.

Submission + - Three Videos on Codec2 and Open Hardware

Bruce Perens writes: Codec2 is the Open Source ultra-low-bandwidth speech codec capable of encoding voice in 1200 Baud. FreeDV (freedv .org) is an HF (global-range radio) implementation that uses half the bandwidth of SSB, and without the noise. Here are three speeches about where it's going:
  • David Rowe: Embedding Codec2: Open Source speech coding on a low-cost microprocessor, at Linux.conf.au 2014. YouTube, downloadable MP4.
  • Bruce Perens: FreeDV, Codec2, and HT of the Future (how we're building a software-defined walkie-talkie that's smarter than a smartphone), at the TAPR/ARRL Digital Communications Conference 2013. Blip.tv, YouTube
  • Chris Testa on the .Whitebox handheld software-defined radio design that is the RF portion of HT of the Future, which was also shown at the TAPR conference.

Comment The economics are wonderful (Score 2) 241

Gee, a $1000 GPU that runs 7x as fast a 1/8th of an $1500 CPU. It woud be good idea if you didn't need that CPU to run it, but just barely so. If you cheap out on the CPU and only spend ~$750 on it, assuminng there is no slowdown on the GPU because of it, then the economics break. And people wonder why GPU compute on databases isn't catching on.

Then there is the power use aka TCO/running costs to think about. And everything mentioned above. And.... This study has all he hallmarks of an Nvidia research project who's targets are financial analysts rather than potential customers. The science is fine but that is not the intent.

            -Charlie

Comment Re:Remember TEMPEST? (Score 2, Insightful) 264

The "audio" in question is most likely all below 24 kHz, that being the Nyquist limit for the 48 kHz sampling hardware, unless it happens that some phones can actually sample faster, and have microphones that can respond to higher frequencies.

The instruction rate of the CPUs in question is many times that frequency.

It doesn't sound likely.

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