Voice codec (coder-decoder)
CML Microcircuits

As a member of the CML DuraTALK® family of digital voice products, the CMX649 Adaptive Delta Modulation (ADM) Voice Codec provides full duplex codec functions optimised for cost effective, portable, wireless applications. Standard and lower cost digital voice applications are supported via selectable operating modes. Robust ADM coding (eg. Continuously Variable Slope Delta modulation (CVSD)) simplifies protocol and host software design by eliminating the forward error correction and framing protocols required by other codec algorithms.

Multiple codec sample/data rates are supported. Integrated filters reduce external components and adjust to match the selected codec sample rate. The use of both external and internal codec sample clock sources is supported.
Independent encoder and decoder powersave controls minimise power for half duplex wireless links.

Baseband interfaces to microphone, loudspeaker, host µC and RF transceiver circuits do not require external transcoders or complex voice frame transfer protocols.