Specialists in Speech and Audio Software Development

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ETSI NB-AMR

The ETSI standard AMR (Adaptive Multi-Rate) narrow band speech codec belongs to the ACELP family of speech coders. Narrow band AMR operates at eight different bit rates from 4.75kbps to 12.2kbps and incorporates the second-generation vocoder standards EFR-GSM (12.2kbps mode) and IS-641-A (7.4kbps mode). Discontinuous transmission (DTX) functionality is also part of the standard with a choice of two different Voice Activity Detection (VAD) algorithms, VAD1 and VAD2. The ESPICO software includes both algorithms. The codec operates on speech frames of 20ms (160 samples) with a 5ms look-ahead.

The ESPICO implementations are highly optimised, realising low memory and MHz requirements. Contact ESPICO for specific resource requirements.

Features

• Encodes and decodes GSM-AMR bit-streams compliant with ETSI GSM 06.90
• Supports Voice Activity Detection (VAD) ETSI GSM 06.93
• Supports Discontinuous Transmission (DTX) ETSI GSM 06.94
• Supports Comfort Noise Generation (CNG)
• Supports substitution and muting of lost frames

Availability

ESPICO’s optimised solution can be ported to any platform. Available solutions include:

• ZSP Cores including ZSP400, ZSP500, ZSP800 families
• ARM including Cortex and NeonTM
• MIPS32 74KTM
• Ceva DSP Cores

Applications

• Digital cellular telecommunications
• VoIP
• Wireless communications
• IP-PBX