CMX608/CMX618/ CML Microcircuits CMX638 COMMUNICATION SEMICONDUCTORS RALCWI Vocoders D/608 18 38/11 September 2014 Provisional Issue Features Applications Near Toll Quality RALCWI Coding Algorithm Digital PMR, LMR, Voice Radio Multiple Bit Rate Modes: Digital Trunking 2400 or 2750 bps DMR TDMA 3600 bps with FEC Enabled 4-bit Viterbi Soft Decision Decoding DMR FDMA, dPMR Integrated Audio CODEC (CMX618/CMX638 only) Digital Voice Scrambling and Encryption Integrated Input and Output Channel Filters Digital WLL 20ms, 40ms, 60ms and 80ms Packet Lengths Voice Storage and Playback Systems No Licensing or Royalty Payments Regenerative Digital Voice Repeaters Ancillary Audio Functions: Messaging Systems Voice Activity Detector VoIP Systems Comfort Noise Generator Voice Pagers DTMF and Single Tone Regeneration 1.8V Low Power Operation, 3.3V Tolerant I/O Half-Duplex Vocoding (CMX608/CMX618) Small 48-pin LQFP and VQFN Packages Full-Duplex Vocoding (CMX638 only) 1. Brief Description The CMX608/CMX618/CMX638 are flexible, high integration, high performance, RALCWI (Robust Advanced Low Complexity Waveform Interpolation) Vocoders, offering near toll quality voice at very low bit rates. A Forward Error Correction (FEC) engine provides optimum performance in real life applications. The RALCWI Vocoder comprises four independent functions which are selectable by the host: Voice Encoder, FEC Encoder, Voice Decoder and FEC Decoder. The CMX608 and CMX618 are half-duplex Vocoders and the CMX638 is a full-duplex Vocoder with integrated voice CODEC.The CMX618 includes an integrated voice CODEC, offering a complete analogue voice to low bit rate vocoded data function, with integrated channel filters removing the need for external components, whereas the CMX608 requires an external voice CODEC. CMX608/CMX618/CMX638 operate from a dual power supply (1.8V and 3.3V) and are available in both 48-pin LQFP (L4) and 48-pin VQFN (Q3) packages. Continued overleaf ..... 2014 CML Microsystems Plc RALCWI Vocoder CMX608/CMX618/CMX638 In encode mode, the voice encoder uses a 20ms voice frame size with two programmable bit rates: 2400bps or 2750bps. The optional FEC encoder performs channel coding of the encoded voice (2400bps or 2750bps, depending on the selected mode) and forms an encoded, interleaved bit-stream of 3600bps (216 bits per 60ms packet or 288 bits per 80ms packet). The FEC operation utilises a packet of either 3 or 4 x 20ms Vocoder frames to provide optimum error correction performance. In decode mode, the optional FEC decoder performs de-interleaving and channel decoding of the coded bit-stream (216 bits per 60ms packet or 288 bits per 80ms packet) and forms an error-corrected bit-stream of encoded voice at 2400bps or 2750bps rate, depending on the selected mode. The FEC decoder can optionally usesoft decisio metrics to improve its decoding ability. The voice decoder then converts the error-corrected bit-stream back into a digitised voice signal. Soft Decision Decoding (SDD), Discontinuous Transmission detection (DTX), Voice Activity Detection (VAD) and Comfort Noise Generation (CNG) functions are also included, to further enhance the overall performance. Single (STD) and Dual (DTMF) Tones can be detected and sent separately in the coded bit- stream, then regenerated at the far end. New features and enhancements to existing functions may be provided from time to time, expanding the capabilities of the Vocoder. These are provided as Function Images, a hex format file that can be loaded via the C-BUS at run-time. Function Images can be downloaded from the CML Portal, a secure area of the CML website. Details of currently available Function Images can be found in the CMX608/CMX618/CMX638 Product page on the CML website. 2014 CML Microsystems Plc 2 D/608 18 38/11