Test Vectors Associated to Rec. ITU-T G.728

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G.728 Appendix I test sequences for implementation verification of the algorithm of the G.728 16 kbit/s LD-CELP speech coder

Provision is included for both floating point implementations, based on the main body of Recommendation G.728, and bit exact fixed point implementations, based on Annex G/G.728.


G.728 Annex J: Variable bit-rate operation of LD-CELP mainly for voiceband-data applications in DCME

This annex provides the information for the implementation of the codec, and the modifications required in Annex G/G.728 to enable a mode-switch, on a fixed-point arithmetic device. Annex J operates at transmission rate of 40 kbit/s. The algorithmic delay is five samples long (0.625 ms), which is exactly the same as Annex G and all LD-CELP algorithms recommended in Recommendation G.728. The 40 kbit/s VBD algorithm in Annex J is intended for VBD signal compression transmission, in applications such as DCME. The algorithm allows soft transition to and from the LD-CELP (Recommendation G.728) algorithm, and is also designed to maintain toll quality speech. Annex J is targeted to replace the 40 kbit/s ADPCM mode (Recommendation G.726) in DCME systems incorporating LD-CELP (Recommendation G.728).

G.728 Annex H: Variable bit rate LD-CELP operation mainly for DCME at rates less than 16 kbit/s

This annex contains the modifications to Recommendation G.728 LD-CELP speech coding algorithm needed to reduce the coding bit rate down to 12.8 and 9.6 kbit/s. These modifications include the modifications to the shape and gain codebooks.
This annex is an optional addition to Recommendation G.728 and is not required in order to correctly implement the encoder and decoder. This annex is intended to enhance the performance of Recommendation G.728 in some specific applications, such as in those to be used with digital circuit multiplication equipment. It is left to the implementers to choose whether to use this annex.