On Tue, Nov 1, 2011 at 5:42 PM, Kristoff Bonne wrote:
> Running on D-STAR is -as far as I see it- not possible; for two reason:
> - Using codec2 in the "DV" (digital voice) mode is incompatible with the
> D-STAR specification. These explicitally say "D-STAR uses AMBE".
Thats nice. If anyone give
On Sun, Nov 27, 2011 at 2:41 PM, acutler22 wrote:
>
> After looking at the LVS exemption though, it points out that *everything*
> packaged with Codec2 must be less than $5000: http://goo.gl/VZPTc
> This could pose an issue of Codec2 were packaged in a large commercial
> telecom product.
> There
On Sun, Nov 27, 2011 at 2:10 PM, acutler22 wrote:
>
> A commentor to David's blog made an interesting discovery, that Codec2 falls
> under the jurisdiction of US export controls now because it's under the 2400
> bit/s bitrate.
It's also probably worth noting that the lowest rate for speex is
2.
On Wed, Feb 1, 2012 at 5:57 PM, Chris Long wrote:
> the purpose of ham radio"? Surely it isn't the progressive narrowing of
> bandwidth to the point where individuality, personality and humanity is
> completely eliminated.
Some of us don't have personality and humanity, you insensitive clod!
;)
On Mon, Feb 13, 2012 at 2:38 PM, Bruce Perens wrote:
> David,
>
> You've definitely revolutionized voice SMS. This is less than 5X English
> ASCII text for the same phrase. And we can do better!
>
> We could start tweeting codec2 voice to each other.
Tweets can take 140 _characters_ but .. since
On Thu, May 10, 2012 at 3:12 AM, Andreas Weller
wrote:
> On Wed, May 9, 2012 at 7:28 PM, Bruce Perens wrote:
>> Hm. Or stay with the lower bit-rate implementation and add LDPC?
>
> I agree on that. This way the interaction of codec, FEC and modem
> could be optimized.
>
> May be one of these LFPC
On Thu, May 10, 2012 at 9:15 PM, Bruce Perens wrote:
> David, Mel, and I have been having a discussion of PAPR: peak vs. average
> power ratio, off of the list. This is also called "crest factor".
[snip]
> Should we compress in software before feeding the amplifier, so that
> clipping is more gra
On Fri, May 11, 2012 at 2:14 PM, Bruce Perens wrote:
> The reason that SSB transmission is in general not offered on HTs is that
> much of the power of a linear PA ends up being turned into heat.
Hm. I thought it was also because they don't have stable and accurate
oscillators (because doing them
On Tue, May 15, 2012 at 6:25 PM, David Rowe wrote:
> Nice work Stuart, very cool what can be done with pipes.
>
> The mod & demod have filter memories that need to fill, and the
> frequency and time acquisition takes a few symbols to acquire. This can
> probably be improved a little. The modem w
On Wed, May 23, 2012 at 11:19 PM, Gullik Webjörn
wrote:
> Since this is a spec, why not? I think the basic idea of a sampling rate
> of 48000 is good, but why not allow 96000 and 192000 as well, allowing
> extension of the spec? After al, hw is available. 48000 should of course
> be the "basic st
On Tue, Jun 12, 2012 at 1:33 PM, Patrick Strasser OE6PSE
wrote:
> Am 11.05.2012 03:44, schrieb Gregory Maxwell:
>> It should be noted that the OFDM modem with N-PSK carriers modulated
>> with a golay complementary sequence (a rate 1/2 FEC) provides a PAPR
>> of 3dB, which I t
On Tue, Jun 12, 2012 at 3:36 PM, Bruce Perens wrote:
> U.S. Amateurs are allowed to transmit incidental music as part of repeating
> NASA spacecraft communications. The rule says "space shuttle", but I'd
> imagine that this is an error and other space vehicles are allowed.
When I first got the CE
On Wed, Dec 5, 2012 at 6:39 PM, Bruce Perens wrote:
> I did a talk at Lawrence Berkeley Lab today. Because the group I am working
> with does a lot of things that look very close to radio, I showed Mel's
> recent video as an example of an Open Source project where we are doing real
> science.
>
>
On Wed, Mar 6, 2013 at 2:48 PM, David Rowe wrote:
> I've been talking to some Turbo Coding and LPDC guys and I now think
> they would be worth testing, for example with block sizes of 256 bits.
> While these codes are optimal at blocks with several thousand bits (a
> few seconds delay of Codec 2)
On Wed, Mar 6, 2013 at 2:40 PM, David Rowe wrote:
> My idea system would work like this. You have some floating point code
> that you annotate, then pass it through a float-fixed compiler/parser.
> The code might look like:
This is how the Opus and Speex stuff works, but the "compiler/parser"
is
On Mon, Mar 11, 2013 at 3:23 PM, Bruce Perens wrote:
> I looked briefly over the U.S. law on this issue since 1927. I think I could
> make a pretty good case that the justifications in 47 CFR 97.1 and the right
> to listen implicit in the 1st amendment to the U.S. constitution imply a
> right to m
On Wed, Apr 17, 2013 at 12:17 PM, Netzblockierer
wrote:
> The Raspberry Pi is a computer.
People who believe this are frequently disappointed. "RPI is a
micro-controller that can run linux" is a more reasonable expectation
in many ways.
On Wed, May 21, 2014 at 5:01 AM, David Rowe wrote:
> Hello List,
>
> I just posted an introduction to SmartMic - an embedded version of
> FreeDV that doesn't need a PC:
>
> http://www.rowetel.com/blog/?p=3125
>
> If would be great if some of the talented readers of this list could
> review
On Mon, Nov 24, 2014 at 6:30 AM, David Rowe wrote:
> Here's the scoop:
>
>http://www.rowetel.com/blog/?p=3700
Very nice results.
You might be interested in some of the interesting things people are
doing with rateless coded modulation,
http://nms.csail.mit.edu/spinal/ ... mostly applicable
On Sat, Dec 13, 2014 at 10:50 PM, David Rowe wrote:
> I've started taking a look at modems for VHF FreeDV, starting with 1200
> bit/s FSK over FM:
>
>http://www.rowetel.com/blog/?p=3799
> Take a look at GMSK.
Make sure you're looking at a sufficiently complex GMSK decoder, when
I looked at t
On Sun, Dec 21, 2014 at 12:05 AM, glen english wrote:
> Easy when you've got a 70K logic cell FPGA, but still possible on
> STM32-4, I think you need to come up with a clever way to run the demod
Well keep in mind that there can be multiple target demodulators for
this. If a modulation scheme is
On Mon, Dec 22, 2014 at 11:54 PM, glen english wrote:
> It is really a bit simpler than all that
> thwere is a drive in mobile comms to increase density.
> For an FM modulation, having four states per symbol instead of two does
> just this, reduces bandwidth.
I think a lot of this is just commerc
On Sun, Feb 8, 2015 at 7:16 AM, Bruce Perens wrote:
> Here are the target features of this version, most of which are already
> tested and working:
Hopefully there will be room to add (or already included) a GPS
receiver. Beyond the very useful direct applications for positioning
(APRS; automatic
On Mon, Feb 16, 2015 at 10:43 PM, glen english wrote:
> I'm excluding space diversity RX for the mobile end (while very very
> effective) because it is a pain
For a HT spatial diversity is obviously nuts. For a mobile-- antenna
on the roof and trunk or on opposite sides is completely reasonable
On Mon, Sep 7, 2015 at 3:18 AM, David Rowe wrote:
> Curiously, I haven't had a _single_ report of a high SNR path that
> breaks FreeDV 700(B). For example a path that works well for SSB, but
> makes the FreeDV 700 modem fall over, would indicate the modem can't
> handle the channel.
Or thar you'
On Tue, Mar 15, 2016 at 11:28 PM, David Rowe wrote:
> Hello Lists,
>
> We've just tested the new FreeDV 2400A mode designed for VHF and above.
> Here's the scoop:
>
>http://www.rowetel.com/blog/?p=5119
Very interesting, -- is there a reason this isn't using a coherent
demodulator beyond dev
On Wed, Mar 23, 2016 at 10:49 PM, glen english wrote:
> should be able to pass continuous random sequence. that sort of testing
> usually finds and breaks clock and bit recovery under pathological
> conditions. testing can take 'quite a while' - days- to test almost every
> conceivable run length
On Mon, Sep 18, 2017 at 9:14 AM, glen english wrote:
> The only real fix is slowing down the symbol rate.
A true diversity receiver is also a real fix.
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On Sun, Feb 24, 2019 at 9:24 PM Jeroen Vreeken wrote:
>
> Hi David,
>
> 52bits per 30ms might work out nicely.
>
> 30ms at 2400baud is 72 bits. If we use a 16 bit uw there are still 4
> bits to spare.
> I don't think FEC is that important when using an existing FM system.
> For more advanced work
On Mon, Mar 4, 2019 at 5:53 PM Adrian Musceac wrote:
> How does this scale for normal hams though? Do each of us need a huge
> GPU and voice samples to even be able to use this? I am afraid that
> this might have even less success with hams than current FreeDV
> releases.
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