GSM/AMR

ADT GSM AMR C54x , C55x , C64x

SPEECH CODER

GSM-AMR is an adaptive multi-rate speech coder that has been standardized for use in Third Generation (3G) mobile telephony .pdf . The coder supports eight bit rates: 12.2, 10.2, 7.95, 7.40, 6.7, 5.9, 5.15, and 4.75 kbps. The coder uses algebraic code excited linear prediction (ACELP) as the compression method. AMR also includes Voice Activity Detection (VAD) and Discontinuous Transmission (DTX) as an added way to save bandwidth by sending fewer bits per second when the user is not speaking. GSM-AMR was developed to maintain high speech quality under a wide range of transmission conditions.

Coding Rate: 12.2, 10.2, 7.95, 7.40, 6.7, 5.9, 5.15, and 4.75 kbps

Sampling Rate: 8 kHz

Delay: 20 milliseconds

FEATURES

Functions are C-callable
Multiple channel capable
Complies with ETSI test vectors. (bit-exact)
Can be integrated with echo cancellers, and tone detection/regeneration.

AVAILABILITY

ADT GSM AMR is available on the TMS320™ DSP Family

C54x™DSP, C55x™DSP, & C64x™DSP Generations .pdf

SPECIFICATIONS

GSM AMR C54x

All Memory usage is given in units of 16-bit word.

Function	MIPS	Program Memory	Data Memory	Per-Channel Data Memory	Scratch Memory
Encode VAD2	18.8	18982	15511	1016	5065
Decode	2.3	7555	13604	608	868
Encode VAD2 / Decode	21.1	25340	16191	1624	5415

Last update: 06/26/2003

GSM AMR C55x

All Memory usage is given in units of byte.

Function	MIPS	Program Memory	Data Memory	Per Cannel Data Memory	Scratch Memory
Encode	17.1	37782	28364	1996	6424
Decode	2.6	19840	28952	1316	1200

Last update: 07/03/2008

GSM AMR C64x

All Memory usage is given in units of byte.

Function	MIPS	Program Memory	Data Memory	Per-Channel Data Memory	Scratch Memory
Encode VAD2	12.0	10086	31082	1992	9360
Decode	2.6	49504	31880	1232	1388
Encode VAD2 / Decoder	14.6	14232	32058	3296	10748

Last update: 12/05/2006

FUNCTION

AMR_ADT_encInit(. . .) Initializes the AMR encoder

AMR_ADT_decInit(. . .) Initializes the AMR decoder

AMR_ADT_encode(. . .) Executes the AMR encoder

AMR_ADT_decode(. . .) Executes the AMR decoder

APPLICATIONS

Wireless base stations and handset " Voice over Packet Gateways

Streaming Media Servers