CML Launches Low Cost, Low Bit-Rate RALCWI Vocoder IC

August 04, 2007 (PRLEAP.COM) Technology News
CML Microcircuits ( a leading innovator and provider of low-power semiconductors for Global Wireless and Wireline communication markets, today announced the introduction of a new RALCWI (Robust Advanced Low Complexity Waveform Interpolation) vocoder IC.

The product is the result of a co-operation between CML Microcircuits and SPIRIT DSP. The new CML IC is named as the CMX618, which CML will market to worldwide communication markets based upon SPIRITís proprietary Low Bit-Rate Vocoder technology. The co-operation combines CMLís 39-year history of developing mixed-signal semiconductors for professional and leisure communication applications, with SPIRITís extensive experience in embedded voice products.

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. The CMX618 offers near toll quality voice performance at very low bit rates, with independent MOS scores indicating that the CMX618 generates sound quality comparable with a standard codec running at bit rates above 4000bps.

The CMX618 includes an integrated voice audio codec, offering a complete analogue voice to low bit rate vocoded data function. There are 3 programmable vocoding rates: 2050bps, 2400bps or 2700bps and when combined with the embedded FEC, provides an overall bit rate of 3600bps. Frame length is selectable from 20, 40, or 60 ms without FEC, 60 or 80 ms 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. Visit: for more information.


About CML
CML Microcircuits (CML) is a member of the CML Microsystems Plc group (LSE: CML.L), specialising in the design, development and marketing of extremely low-power semiconductor products for Global Wireless and Wireline communications applications. Founded in 1968, the company is headquartered near London, UK with strategic locations in the USA, Singapore and China.

Since inception in 1992 SPIRIT ( has become a global brand in top quality voice, audio and data communication software products and is well known for innovation. SPIRIT delivers embedded voice, audio, video and communication products and consulting services to the world's leading telecommunication equipment and semiconductor vendors, collaboration software vendors and mobile OEMs/ODMs. SPIRIT engineers and experience allow the company to offer complete and highly optimized solutions, as well as delivering high quality professional integration services and support. SPIRIT is actively engaged in R&D for state-of-the-art communications solutions.

CML contact
Mark Channen, Marcoms Officer
tel. +44 (0)1621 875500

SPIRIT DSP contact:
Ksenia Egorova, Public Relations Manager
tel. +7 (495) 911 7654