6 Jun 2010 03:12
6 Jun 2010 10:05
Re: Echo Test
On Sat, 5 Jun 2010 18:12:29 -0700 (PDT) a cutler22 <acutler22@...> wrote: > Echo, Echo Echo.... Any reverberations? ;) It's certainly quiet, but there are others listening.... -- -- Brian Morrison "I am not young enough to know everything" Oscar Wilde
21 Jun 2010 00:01
Codec for amateur radio use
Hello everyone,
Just noticed Codec2 as reported in the July RSGB Newsletter - the test follows:
• The D-Star protocol developed by the
Japanese Amateur Radio League (JARL)
is open and freely available. However, the
AMBE voice encoding scheme currently
used by the D-Star protocol is patented
by DVSI, Inc. Development on an open
source, freely available alternative to
AMBE has been spearheaded by David
Rowe, VK5DGR. This open voice codec is
called Codec2 and is in a highly experimental
stage at this current point. Learn more at
www.rowetel.com/blog/?p=128.
Am interested to hear if an alternative to D Star exists. It seem that digital voice offers all kinds of development possibilities that D Star doesn't bring out. For example full duplex on same channel using TDD, diversity receivers via repeaters on same channel using TDD etc etc.
I have looked into SPEEX but was much too slow on a DSPIC. Also have implemented a half duplex DV system using the CMX618: Half-duplex RALCWI Vocoder with Integrated Voice Codec. This works well but you have to buy the chip so not really suitable for amateur radio.
I would be interested to hear of an open source codec that would run on a DSPIC or similar as that would open the door to lots of interesting developments.
Best wishes
Simon
G8PAN
__________________________________________________________________________________
www.wvars.com Simplex FM frequencies: 29.600MHz, 70.450MHz, 145.275MHz, 433.475MHz
Link frequencies: Echolink: G1IVG-L 430.0125MHz (77Hz),
Just noticed Codec2 as reported in the July RSGB Newsletter - the test follows:
• The D-Star protocol developed by the
Japanese Amateur Radio League (JARL)
is open and freely available. However, the
AMBE voice encoding scheme currently
used by the D-Star protocol is patented
by DVSI, Inc. Development on an open
source, freely available alternative to
AMBE has been spearheaded by David
Rowe, VK5DGR. This open voice codec is
called Codec2 and is in a highly experimental
stage at this current point. Learn more at
www.rowetel.com/blog/?p=128.
Am interested to hear if an alternative to D Star exists. It seem that digital voice offers all kinds of development possibilities that D Star doesn't bring out. For example full duplex on same channel using TDD, diversity receivers via repeaters on same channel using TDD etc etc.
I have looked into SPEEX but was much too slow on a DSPIC. Also have implemented a half duplex DV system using the CMX618: Half-duplex RALCWI Vocoder with Integrated Voice Codec. This works well but you have to buy the chip so not really suitable for amateur radio.
I would be interested to hear of an open source codec that would run on a DSPIC or similar as that would open the door to lots of interesting developments.
Best wishes
Simon
G8PAN
__________________________________________________________________________________
www.wvars.com Simplex FM frequencies: 29.600MHz, 70.450MHz, 145.275MHz, 433.475MHz
Link frequencies: Echolink: G1IVG-L 430.0125MHz (77Hz),
21 Jun 2010 01:07
Re: Codec for amateur radio use
On Sun, Jun 20, 2010 at 6:01 PM, Simon W Day <swd@...> wrote: > I have looked into SPEEX but was much too slow on a DSPIC. Also have > implemented a half duplex DV system using the CMX618: Half-duplex RALCWI > Vocoder with Integrated Voice Codec. This works well but you have to buy the > chip so not really suitable for amateur radio. I don't think anyone is going to do much interesting decompression with less CPU required than _speex_. (Speex compression complexity is another matter— the complexity of a speex compressor could be almost as cheap as the decompressor but low quality or much faster).
21 Jun 2010 01:14
Re: Codec for amateur radio use
> I have looked into SPEEX but was much too slow on a DSPIC. Also have > implemented a half duplex DV system using the *CMX618:* Half-duplex > RALCWI Vocoder with Integrated Voice Codec. This works well but you have > to buy the chip so not really suitable for amateur radio. > > I would be interested to hear of an open source codec that would run on > a DSPIC or similar as that would open the door to lots of interesting > developments. You mean something like this: http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023610 Jean-Marc
21 Jun 2010 10:35
Re: Codec for amateur radio use
Hi There, Thanks for the two helpful responses to my message: The Microchip SPEEX seems to be written in a highly optimised assembler and so isn't an easy point to start from. However PIC32 have appeared since then so it could be that the SPEEX C code would run on that processor. I've not have chance to investigate that. To allow the greatest number of radio amateurs to get involved with experimenting with TDD etc, the development tools would need to be as straight forward as possible. This suggests C code to me. Best wishes Simon G8PAN At 19:14 20/06/2010 -0400, Jean-Marc Valin wrote: >>I have looked into SPEEX but was much too slow on a DSPIC. Also have >>implemented a half duplex DV system using the *CMX618:* Half-duplex >>RALCWI Vocoder with Integrated Voice Codec. This works well but you have >>to buy the chip so not really suitable for amateur radio. >> >>I would be interested to hear of an open source codec that would run on >>a DSPIC or similar as that would open the door to lots of interesting >>developments. > >You mean something like this: >http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en023610 > > Jean-Marc > I don't think anyone is going to do much interesting decompression with less CPU required than _speex_. (Speex compression complexity is another matterthe complexity of a speex compressor could be almosst as cheap as the decompressor but low quality or much faster). __________________________________________________________________________________ www.wvars.com Simplex FM frequencies: 29.600MHz, 70.450MHz, 145.275MHz, 433.475MHz Link frequencies: Echolink: G1IVG-L 430.0125MHz (77Hz),
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