User`s manual

EAGLE
Multi-Standard Dual-Channel Digital Audio Codec
5
In the following Coding Algorithms, the Eagle both, transmits and receives on the same
Encoding Algorithms:
- G.711: By using this algorithm it is possible to generate and receive voice calls, and to establish
communication through ISDN with telephone numbers or lines pertaining to the basic and
analogue telephone network (PSTN).
- G.722: This mode is widely accepted for bi-directional communication, thanks to the low delay
induced, it is frequently used for voice-overs and commentator applications such as sport
coverage.
- The G.722 H221/H242 mode provides a bi-directional ancillary data channel
simultaneously with the Audio transmission.
- The statistical G.722 mode is performing a real-time Audio processing of the
transmitted Audio signal that allows a continuous bandwidth adjustment, which improves
the quality of some Audio signals, for example the voice of a sport commentator. In this
case no ancillary data channel is needed.
- MPEG Layer II: Very well known and accepted encoding mode, used when delay is not a factor,
as MPEG modes always have higher delay than G.722 modes. The EAGLE includes MPEG LII
for mono, dual or stereo transmission.
The equipment implements two different framing modes for the transmission of 128 KBPS
programs in MPEG Layer II, combining the two 64 KBPS B-channels of the ISDN line:
 J.52 Multiplexing: J.52 is the international standard that defines how to frame and
transmit a Multi-channel. In the EAGLE, two 64 KBPS channels are framed and
transmitted.
 IMUX (Recommended mode): Framing for 128 KBPS modes, implemented for
compatibility with other equipment that are available on the market. This framing mode
also offers a lower delay than the J.52 framing mode.
The framing modes are selected in the menu “8. Defaults”
- MPEG Layer III: very well-known and accepted algorithm that presents better Audio
bandwidth at lower bit rates but at the cost of a longer encoding and decoding delay. The
EAGLE includes MPEG LIII for transmission in mono or stereo.
 In order for MPEG Layer III at 128kbps to function properly the IMUX framing mode must
be selected.
 In the transmission modes of MPEG Layer III at 64kbps only channel 1 can be used.
 In the MPEG Layer III modes it is not possible to generate DTMF tones.
 In the MPEG Layer III it is possible to use different modes simultaneously within a single
transmission, for example MONO and STEREO within the same communication.
MPEG Layer-3 audio coding technology licensed from Fraunhofer IIS and Thomson
AEQ LD-2: AEQ proprietary mode (based on the previous AEQ LD-EXTEND) combining the low
delay of the G.722 with the greater bandwidth of MPEG, thus optimizing both modes. It can only
be used if there is equipment with the same encoding mode at the other end, i.e., another
EAGLE, a COURSE, the AEQ model ACD-5001 (stationary) or an MPAC-02.
 If you have older AEQ CODECS that implement the AEQ LD-EXTEND and want to
make them compatible with the EAGLE in this algorithm, visit our web-site
http://www.aeq.es/ and upgrade them to the latest firmware version available.
In the SPLIT modes, the transmission (encoding) is independent of the reception (decoding).
This system allows you to receive a high quality Program Audio Signal from an event with a
relatively low quality Return Audio Signal with low delay.
- SPLIT MODE: Allows to transmit in MPEG L3 64 MONO 48kHz (high quality) and to
receive in G722 STAT (low delay) using only a single B-channel of the line ISDN line. The
second B-channel of the ISDN line cannot be used. Evidently, the Audio Codec that receives the
signal will have to carry out the inverse operation, to receive in MPEG L3 64 MONO 48kHz and to
transmit in G722. To set up an EAGLE for this mode, “cMP3 dG722” should be selected and the
remote EAGLE should be set to “cG722 dMP3”.
In this Audio Codec, the encoding modes can be changed once a communication has been
established and without the need of interrupting it thanks to the Terminal Adapter implemented
in the equipment. When a connection at 128kbps is changed for one of 64kbps, channel 2 will
be disconnected.