Re: [DSTAR_DIGITAL] Codec2 development - open source vocoder

2010-06-11 Thread Tony Langdon
>If any of you speak the C language he could use your hand! At the >very least, getting Codec2 to a Unfortunately, I don't. :( > beta-testing stage would be exciting to say the least! However, it > won't happen without community support. Well, when it gets to the point that some beta testing

Re: [DSTAR_DIGITAL] Codec2 development - open source vocoder

2010-06-11 Thread a cutler22
Nor do I know C that well... that's why I'm getting the word out - anyone can help spread the word about Codec2 and its development. My overt zeal may have ticked a few people off, so I would recommend a more cooler-headed approach :) -73, KE7HQY From: Tony L

Re: [DSTAR_DIGITAL] Codec2 development - open source vocoder

2010-06-11 Thread Robbie De Lise
I know a little bit of C, no C++ though. And I think my knowledge would really not be suffice to do something like this. 73s Robbie ON4SAX On Fri, Jun 11, 2010 at 8:27 AM, a cutler22 wrote: > > > Nor do I know C that well... > > that's why I'm getting the word out - *anyone* can help spread the

Re: [DSTAR_DIGITAL] Codec2 development - open source vocoder

2010-06-11 Thread a cutler22
Going strictly from emails I've exchanged with David, it sounds like he has some "grunt" work in C, which he could offload to someone else to take over while he focused on DSP programming, etc. Right on his website he states: "Not all of this project is DSP. There are many general C coding task

[DSTAR_DIGITAL] Codec2 Developer InterviewInterview

2010-06-11 Thread a cutler22
There's also a really great interview with David Rowe, VK5DGR that gives a lot of background on his history, extensive experience in codecs and his future aspirations. The interview is from Oct. 2008: http://www.cio.com.au/article/264806/open_source_identity_free_telephony_project_founder_david_

Re: [DSTAR_DIGITAL] Codec2 development - open source vocoder

2010-06-11 Thread Storer, Darren
Hi Jim, you mention using wider bandwidth at VHF but this isn't a realistic option for use in IARU region 1, where 12.5 KHz channel spacing was adopted back in 1996. It was always worrying that Bruce repeatedly referred to 9K6 data rates for his DV codec work but wasn't able to demonstrate a metho

[DSTAR_DIGITAL] Re: Codec2 development - open source vocoder

2010-06-11 Thread Jonathan Naylor
Getting 9600 Bd into 12.5 kHz isn't too difficult as long as you're willing to sacrifice weak signal performance, Shannons law tells us that. I would imagine OFDM or even m-ary PSK would be capable of providing the required throughput. The big advantage that GMSK has for manufacturers is that th

Re: [DSTAR_DIGITAL] Re: Codec2 development - open source vocoder

2010-06-11 Thread Storer, Darren
Hi Jonathan, fortunately the AMBE chip is so efficient that we don't have to start running QPSK/OFDM and changing over to ultra linear PAs, like we have for Digital ATV. It seems churlish to suggest that everyone change their radios, repeaters and power amplifiers, just to cope with the deficienc

Re: [DSTAR_DIGITAL] Re: Codec2 development - open source vocoder

2010-06-11 Thread Tony Langdon
At 11:56 PM 6/11/2010, you wrote: >The answer to why there's a push for 6.25 KHz, >could best be answered during a chat with G4TSN, >who will fill you in on how hard it is to get >new kit on the air on VHF, especially near >conurbations. This problem exists across much of >Europe and the US,