Ambe Vocoder Software
Contents.Overview In 1967 Osamu Fujimura showed basic advantages of the multi-band representation of speech ('An Approximation to Voice Aperiodicity', IEEE 1968). This work gave a start to development of the 'multi-band excitation' method of speech coding, that was patented in 1997 (now expired) by founders of DVSI as 'Multi-Band Excitation' (MBE). All consequent improvements known as Improved Multi-Band Excitation (IMBE), Advanced Multiband Excitation (AMBE), AMBE+ and AMBE+2 are based on this MBE method.AMBE is a -based that operates at of between 2 and 9.6 kbit/s, and at a sampling rate of 8 kHz in 20-ms frames. The audio data is usually combined with up to 7 bit/s of data, producing a total RF bandwidth of approximately 2,250 Hz (compared to 2,700–3,000 Hz for an analogue single sideband transmission). Lost frames can be masked by using the parameters of the previous frame to fill in the gap.Usage AMBE is used by the and systems and certain channels on and is the for.AMBE is used in digital voice communications. It has met criticism from the amateur radio community because the nature of its and licensing runs counter to the openness of amateur radio, as well as usage restriction for being 'undisclosed digital code' under and similar national legislation.The digital voice and data protocol uses the AMBE+2 codec. Is implemented by Icom in the IDAS system and by Kenwood as NEXEDGE.Phase 2 trunked radio systems also use the AMBE+2 codec, while Phase 1 radios use the earlier IMBE codec.(DMR) and Motorola's MOTOTRBO use the AMBE+2 codec.Licensing Use of the AMBE standard requires a license from Digital Voice Systems, Inc.
Digital Speech Decoder is an open source software package that decodes several digital speech formats. It uses the mbelib library (a separate open source package) to synthesize the decoded digital speech. It does not allow decoding of encrypted communications. The open source software was unveiled by anonymous authors in May 2010. Spider man game 128 160. It seems to have possibly stemmed from the May 2008 OP25 project, that provides a software IMBE voice encoder/decoder. APCO Project 25 traces back to the early 1990's required publication of the IMBE and AMBE codec algorithms, which of course is how both projects came about. AMBE+2™ vocoder software libraries are available under license for a variety of Digital Signal Processors (DSPs), plus general and application CPUs including.
While a licensing fee is due for most codecs, DVSI does not disclose software licensing terms. Anecdotal evidence suggests that licensing fee begin from between $100,000 to $1 million. For purposes of comparison, licensing fees for use of the standard started at $15,000. For small-scale use and prototyping, the only option is to purchase a dedicated hardware IC from DVSI.
DSP Innovations Inc. Offers a software implementation of APCO P25 Phase 1 (Full-Rate) and Phase 2 (Half-Rate) codecs as well as DMR and dPMR codecs.
A technology licence from DVSI is required.The patent for IMBE has expired.Alternatives is an open source alternative which uses half of the bandwidth of AMBE to encode speech of similar quality, created by David Rowe and lobbied. Codec2 still continues to evolve, with additional 'modes' being developed, refined and made available on a continuous basis. This has resulted in an open source codec that has progressively increased its robustness and performance – when subjected to some of the most challenging RF and acoustic environments. References.
Free Vocoder Software For Mac
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It is YOUR responsibility to properly word your request.To obtain Motorola software see the Sticky in the Motorola forum.The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500.
The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this. 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.orgThis 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?