November 24, 2011 - DSP Innovations Inc. (DSPINI) announces proprietary 2400 bps vocoder, based on the newest speech coding technology TWELP™, for DMR/dPMR and other markets.
TWELP™ technology features. The vocoder is based on newest technology of speech coding called "Tri-Wave Excited Linear Prediction"™ (TWELP) that was developed by experts of DSPINI. The technology provides the best speech quality among competitors today. Please visit: http://twelp.pro for details.
Superiority in speech quality. Here is the comparison with AMBE+2 vocoder. TWELP 2400 bps vocoder and AMBE-3000 HDK (Rate#33: AMBE+2 2450 bps vocoder) were tested, using ITU-T P.50 speech base for 20 different languages. ITU-T P.862 utility was used for estimation of the speech quality in PESQ terms:
A diagram demonstrates significant superiority of TWELP over AMBE+2 and MELPe in speech quality.
A few independent experts tested by listening TWELP vocoder in comparison with AMBE+2 and MELPe 2400, using method of preferences. Majority of experts preferred AMBE+2 to MELPe and significant majority of the experts preferred TWELP to AMBE+2 and MELPe, having noted much more natural human-sounding of voice in the TWELP vocoder.
Superiority in quality of the non-speech signals. In contrast to other LBR vocoders (MELPe, AMBE+2, etc.), TWELP vocoders provide high quality of non-speech signals, including police, ambulance, fire sirens, etc. This feature in conjunction with high quality natural human-sounding of voice makes TWELP vocoders well suitable for replacement of analog radio by digital radio and also for other applications where high quality transmitting of non-speech signals is relevant along with high quality transmitting of speech signals.
High robustness to acoustic noise. In contrast to other LBR vocoders, TWELP vocoders are well robust to acoustic noise thanks to robust reliable method of pitch estimation and other features of TWELP technology.
High Robustness to the channel errors. "Robust" versions of the TWELP vocoders include FEC that are integrated with vocoder on base of "joint source-channel coding" approach that provides high speech quality simultaneously in noisy channel as well as in noiseless channel. FEC can operate with "soft decisions" as well as with "hard decisions" from a modem. Mode of "soft decisions" provides much better robustness in comparison with mode of "hard decisions".
Additional functionalities. The following additional functionalities are developed by DSPINI and integrated into TWELP vocoders:
Technical characteristics and resource requirements:
|Algorithmic delay (including farme size)
|Signal format||Bit stream format|
|AGC||Automatic Gain Control||Control range:||0 ... +20 dB|
|NCSE||Noise Canceller -
|SNR increasing||> 6 dB|
|Speech quality improvement||> 0.1 PESQ|
|Single/Dual tones detection||In accordance with international standards|
|Single/Dual tones generation||Special generator, kept continuity of signal (phase and amplitude of signal of previous frame)|
|VAD||Voice Activity Detection||Reliable detection speech in background noise|
|CNG||Comfort Noise Generation||Type of noise||"white"|
|Level||- 60 dB|
|Voice Encoder + Voice Decoder||60.8|
* MIPS is measured on STM32F4DISCOVERY board by usage of cycle counter register DWT_CYCCNT.
* Program and tables are placed in Flash memory.
* State, heap and stack are placed in RAM memory.
Note that floating point unit (FPU) is not used.
|Voice Encoder + Voice Decoder||22.4|
|Voice Encoder + Voice Decoder||42|
* DSPINI continues optimization of the TWELP algorithm and code in order to minimize computational complexity of the vocoder.
Guarantee and support. DSPINI guarantees a quality and accordance of all technical characteristics of the product to requirement of current specifications. Testing and other method of quality control are used for guarantee support.
Any platform. DSPINI can port this vocoder software into any other DSP, RISC or general- purposes platform inshort time: 2-3 months.
Licensing terms. To use the vocoder, customer should obtain a license from DSPINI only.
Low price is another advantage of this vocoder. Please contact us to check it out.
Prospects. DSPINI are developing a set of new vocoders with range from 600 bps up to 9600 bps, based on TWELP technology. Please visit the http://twelp.pro web-site to get more information.
Related software. This vocoder may be effectively used in a bundle with other DSPINI's products:
More DSPINI's products on http://www.dspini.com
Please contact to evaluate and purchase:
|DSP INNOVATIONS INC.|
|Tel/Fax:||+44 20 8133 00 44|
Tri-Wave Excited Linear Prediction, TWELP, DSPINI and DSP Innovations logo are trademarks of DSP Innovations Inc. AMBE-3000 and AMBE+2 are trademarks of Digital Voice Systems Inc.
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