Selectable Mode Vocoder
SMV IS VARIABLE BITRATE SPEECH CODING STANDARD USED IN CDMA* NETWORKS
- Functions are C-callable
- Designed for Multi-channel operation
- Completely re–entrant (Channel can interrupt any Channel, any time)
- Includes Packet Loss Concealment Algorithm
- Includes Support for Discontinuous Transmission (DTX)
- Includes optional noise suppression
Platforms Texas Instruments – TI TMS320C6000 C64x / C64x+/ C66x / C674x
Coding Rate: 8.55 4.0, or 2.0 kbps
Sampling Rate: 8 kHz
Delay: 20 milliseconds
ADT SMV is available on the above Platforms: Other configurations are available upon request.
The Adaptive Digital Technologies Selectable Mode Vocoder (SMV)is a real-time implementation of the 3GPP2 standardized speech codec. The vocoder, originally developed for cellular telephony, also has other applications in VoIP.
SMV provides a number of operating points, or average bit rate set points, allowing operators to make their own voice quality/system capacity trade-offs. These trade-offs can be made on a static basis, such as call set-up, or on a dynamic basis, allowing for a reduction in voice quality to manage localized capacity problems.
SMV is required to operate at a number of average bit rate setpoints, allowing for each service provider to perform their own voice quality/system capacity trade off. As a result, the SMV design includes multiple modes; each associated with an average bit rate limitation.
*Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies.
API function call summary
SMVDEC_ADT_init Initializes an Decode Channel
SMVENC_ADT_encode Encodes a frame of data
SMVDEC_ADT_decode Decodes a frame of data