Re: P25?


"John D. Hays" <john@...>
 

I am familiar with the package -- NW Digital Radio would not be inclined to directly support it, due to the following:

Patent Issues with mbelib

While DSD was intended to be patent-free, mbelib describes functions that may be covered by one or more U.S. patents owned by DVSI Inc. The source code itself should not be infringing as it merely describes possible methods of implementation. Compiling or using mbelib may infringe on patents rights and/or require licensing. It is unknown if DVSI will sell licenses for software that uses mbelib. If you do not have a license and are in a jurisdiction protected by the DVSI patents you should not compile or use this source code. 


-- from the project site.


If the mbelib is not used, the rest of the code might be worth study by a developer.   P25 Phase 2 does use an AMBE chip (newer than the one D-STAR uses --  We are studying using the newest 3000 series chip in our daughter card).  Phase 1 uses the incompatible IMBE vocoder.



John D. Hays
K7VE
PO Box 1223, Edmonds, WA 98020-1223 
  



On Tue, Jun 5, 2012 at 5:13 PM, William Stillwell - KI4SWY <wkstill@...> wrote:
 

Not sure if any of you have seen this:

http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_%28software_
package%29

Linux Based Decoder Software that supports:

• P25 Phase 1
• ProVoice EDACS Digital voice
• X2-TDMA - Motorola public safety TDMA system with P25 style signaling
(mostly based on DMR)
• DMR/MOTOTRBO - Digital Mobile Radio standard
• NXDN - 9600 baud (12.5 kHz) NEXEDGE and 4800 baud (6.25 kHz) NEXEDGE/IDAS
• C4FM modulation
• GFSK modulation (including GMSK and other filtered 2/4 level FSK)
• QPSK modulation (sometimes marketed as "LSM")

The following formats are currently under investigation or development:
• P25 Phase 2 - standard not finalized yet, vocoder is supported by mbelib
• OpenSky - four slot format vocoder may be supported by mbelib. Will not be
supportable if it is determined that voice encryption is not optional
• D-STAR - Voice frames recognized, vocoder not supported by mbelib. May be
possible to pass voice bits to DVDongle.
• Other formats will only be considered if high quality samples of the
signals are made available for download by the developers. Samples must be
from a discriminator tap, .wav format, 48000Hz, 16 bits per sample, mono.

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