freddaniel
Member
It seems Digital Voice Systems has a lock on the preferred vocoder for use in LMR equipment. DVS got IMBE into P25 years ago, and it is now won acceptance of the newer AMBE+2 vocoder. The excellent voice quality of the AMBE+2 has also captured the favored position in almost every standard, such as DMR, dPMR, NXDN and others. Sticking with a DVS solution also allows for backward compatibility to IMBE, if desired. However, the Amateur Radio D-Star project which also started with IMBE found the cost to use a DVS brand vocoder was costly. Even today, to use a dedicated AMBE-3000 processor or license their software, still adds at least $30 cost to every radio. This single cost alone could raise the retail price by $200.
This may not seem significant for a radio that sells for $750 to $2,500 each, but everyday breakthroughs are occurring in vocoder technology. There is even renewed open spec & open source efforts building, much like Linux and Apache have replaced Microsoft in the web server market. Examples of some of these vocoders are:
TWELP – Otherwise known as Tri-Wave Excited Linear Prediction™ coding offered by DSP Innovations in Russia, with reportedly significantly higher acceptance values than AMBE+2, at a reasonable price.
SILK – Developed by Skype for their use, is now freely available. Not a good fit, but may be adaptable in the future.
Codec 2 – An open source low bit rate speech codec designed for communications quality speech being developed by rowetel.com, as time and funds permit. Now in alpha testing.
Speex – As open source codec being developed. See speex.org
This is just a sampling of what is in the pipeline. Another consideration is the availability from CML of the new CMX8341 Baseband processor that includes the TWELP codec. This can be added to a 12.5 KHz analog radio to provide dPMR or NXDN compatibility for under $15.
Finally, in Q1 of 2012, Freescale (previously Motorola Semiconductor) will release production quantities of the MC13260 system-on-chip. This is an entire radio on a chip, except preselector, and power amplifier for 60 to 960 MHz, under $15.
What say you?
This may not seem significant for a radio that sells for $750 to $2,500 each, but everyday breakthroughs are occurring in vocoder technology. There is even renewed open spec & open source efforts building, much like Linux and Apache have replaced Microsoft in the web server market. Examples of some of these vocoders are:
TWELP – Otherwise known as Tri-Wave Excited Linear Prediction™ coding offered by DSP Innovations in Russia, with reportedly significantly higher acceptance values than AMBE+2, at a reasonable price.
SILK – Developed by Skype for their use, is now freely available. Not a good fit, but may be adaptable in the future.
Codec 2 – An open source low bit rate speech codec designed for communications quality speech being developed by rowetel.com, as time and funds permit. Now in alpha testing.
Speex – As open source codec being developed. See speex.org
This is just a sampling of what is in the pipeline. Another consideration is the availability from CML of the new CMX8341 Baseband processor that includes the TWELP codec. This can be added to a 12.5 KHz analog radio to provide dPMR or NXDN compatibility for under $15.
Finally, in Q1 of 2012, Freescale (previously Motorola Semiconductor) will release production quantities of the MC13260 system-on-chip. This is an entire radio on a chip, except preselector, and power amplifier for 60 to 960 MHz, under $15.
What say you?