scope:

This ETS contains the full specification of the speech codec for use in the Trans-European Trunked Radio (TETRA) system.

Clause 4 provides a complete description of the full rate speech source encoder and decoder, whilst clause 5 describes the speech channel encoder, and clause 6 the speech channel decoder.

Clause 7 describes the codec performance, including the minimum required speech channel decoder performance.

Finally, clause 8 introduces the bit exact description of the codec. This description is given as an ANSI C code, fixed point, bit exact. The whole C code corresponding to the TETRA codec is given in computer files attached to this ETS, and are an integral part of this ETS.

In addition to these clauses, five informative annexes are provided.

Annex A describes a possible implementation of the speech channel decoding function.

Annex B provides comprehensive indexes of all the routines and files included in the C code associated with this ETS.

Annex C lists informative references relevant to the speech codec.

Annex D describes the actual quality, performance and complexity aspects of the codec.

Annex E reports detailed results from codec characterisation listening and complexity tests.

Annex F contains instructions for the use of the attached diskette.