Advanced Multi-Band Excitation

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Advanced Multi-Band Excitation (AMBE) is a proprietary speech coding standard developed by Digital Voice Systems, Inc..

1 Features
2 Technology
3 History
4 Usage
5 Licensing
6 References
7 External links

Features

AMBE operates at bitrates of between 2000 and 9600 bit/s. The audio data is usually combined with up to 7 bit/s of forward error correction data to produce a total RF bandwidth of approximately 2250 Hz (compared to 2700–3000 Hz for an analog single sideband transmission). This has the effect of increasing sound quality and removing static from HF communications. Lost frames can be masked by using the parameters of the previous frame to fill in the gap.

Technology

AMBE is based on Codebooks and works at a sampling rate of 8 kHz in frames of 20 ms.

History

1980 Multi-Band Excitation (MBE) was developed at the MIT. DVSI improved MBE-technology which led to their Improved Multi-Band Excitation (IMBE). AMBE is a successor to IMBE.

Usage

It is used by the Inmarsat and Iridium satellite telephony systems and certain channels on XM Satellite Radio and is the speech coder for OpenSky Trunked radio systems.

AMBE is used in D-Star amateur radio digital voice communications. It has met criticism because its patented nature runs counter to the openness of amateur radio.^[1]

Licensing

AMBE requires a license from Digital Voice Systems, Inc.. While a licensing fee is due for most codecs, DVSI does not disclose software licensing terms. Anecdotal evidence suggests a minimum fee from $100,000 to $1 Million. PC implementations are not allowed. For the purposes of comparison, MP3's licensing starts at $15,000. For small-scale use and prototyping, the only option is to purchase a dedicated hardware IC from DVSI.