Product category:
Communications ICs (Wired)
News Release from: CML Microcircuits | Subject: CMX618
Edited by the Electronicstalk Editorial
Team on 03 August 2007
Vocoder IC exploits Spirit's voice
technologies
The CMX618 is a flexible, half-duplex, highly integrated RALCWI vocoder IC suited to both wireless and wireline voice applications.
CML Microcircuits has developed a new RALCWI (robust advanced low complexity waveform interpolation) vocoder IC in collaboration with Spirit DSP The CMX618 is based on Spirit's proprietary low bitrate vocoder technology
This article was originally published on Electronicstalk on 11 Feb 2004 at 8.00am (UK)
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The CMX618 is a flexible, half-duplex, highly integrated RALCWI vocoder IC suited to both wireless and wireline voice applications such as voice scramblers, alarm systems, military field applications and digital professional/leisure two-way radios (DMR/dPMR) to name but a few examples.
RALCWI technology uses proprietary signal decomposition and parameter encoding methods, ensuring high speech quality at high compression rates.
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The CMX618 offers near toll quality voice performance at very low bitrates, with independent MOS scores indicating that the CMX618 generates sound quality comparable with a standard codec running at bitrates above 4000bit/s.
The CMX618 includes an integrated voice audio codec, offering a complete analogue voice to low bit rate vocoded data function.
There are three programmable vocoding rates - 2050, 2400 or 2700bit/s - and when combined with the embedded FEC, this provides an overall bitrate of 3600bit/s.
Frame length is selectable from 20, 40 or 60ms without FEC, 60 or 80ms can be selected with FEC protected frames.
The selectable integral Viterbi decoder can use soft-decision metrics to improve its decoding ability.
The FEC can also be used separately, so that data can be decoded/error-corrected, then re-encoded and forwarded on.
This feature is particularly useful in voice repeaters, providing optimal voice performance and maximum range.
CML also offers designers the CMX608, a vocoder option without the integrated audio codec.
This enables the use of an external audio codec solution.
Both the CMX618 and CMX608 are free from any licence and royalty costs, fully meeting the requirements of high performance low bit rate digital voice applications.
The CMX618 and CMX608 are available in small low power 48-pin VQFN and LQFP packages.
An evaluation kit is available (EV6180), facilitating quick and easy evaluation.
Connections are provided for audio input and output, power supply and a serial bus (C-Bus) header for connection to a host microcontroller.
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