CMX649

Features:

Multiple Codec Modes, 16 to 128 kbps
Full duplex ADM and CVSD
Full duplex PCM: |-law, A-law, Linear
Configurable ADM time constants
Dual channel transcoder/decoder mode  
High Performance Digital Architecture  
Low Power: 2.5mA at 3.0V typ.  
2.7V - 5.5V Supply  
Data Clock Recovery  
Programmable Voice Activity Detector  (VAD)
Adjust threshold level and attack/decay time 
Use to powersave on low signal level
Silence/blank low level signals  
Programmable Digital Scrambler  
Flexible Interfaces
8-bit and 16-bit burst data with sync strobe
1 bit serial data with clock
Host serial control/data interface 
Internal and External Sample Clocking  
Programmable Filters
Encoder mic input ADC anti-alias
Decoder audio out DAC anti-imaging  
Low Noise Differential Mic Input Amp  
Programmable Analog Interface Gain
Microphone in
Decoder audio out
Sidetone path



Application

Low Cost Digital Cordless Headset
Personal Area Network (PAN) Voice Link
Digital Cordless Telephone
Wireless Digital PBX
Full Duplex Digital Radio Systems
Time Division Duplex (TDD) Systems
Portable Digital Voice Communicator
Digital Voice Delay


Specifications




Description

The CMX649 Adaptive Delta Modulation (ADM) Voice Codec provides full duplex ADM, companded (/A-law) PCM and linear PCM codec and transcoder functions for cost effecive, low power, wireless voice applications.  Selectable modes and algorithms support many applications. Robust ADM coding (e.g. CVSD) reduces host protocol and software burdens, eliminating forward error correction, framing protocols and algorithm processing.  Dual transcode/decode mode supports multichannel applications Integrated filter responses adjust independent of 16kbps to 128kbps codec data rates. Codec sample clocks are externally applied or internally generated. High performance analog interfaces and sideton include digital gain controls. Encoder and decoder voice activity detectors support powersaving.
The CMX649 ADM Voice Codec supports 2.7V to 5.5V operation and is available in 20-pin SOIC (D3)and TSSOP packages (E3) packages.