Q67101-H6773 Просмотр технического описания (PDF) - Infineon Technologies

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Q67101-H6773

Joint Audio Decoder-Encoder - Multimode

Infineon Technologies 

PSB 7238

1

Introduction

Introduction

1.1

Overview

The PSB 7238 Joint Audio Decoder Encoder Multimode (JADE MM) is a device which

implements voice compression algorithms using the Low-Delay Code Excited Linear

Prediction (LD-CELP) standard as defined in the ITU-T G.728 Recommendation, the

Algebraic Code Excited Linear Prediction (ACELP) and the Multi-Pulse Maximum

Likelihood Quantization (MP-MLQ) standard as defined in the ITU-T G.723

Recommendation, and for 7-kHz voice using the Sub-Band Coded Adaptive Differential

PCM (SBC-ADPCM) coding according to the G.722 Recommendation. In addition G.711

PCM audio coding is also supported.

Thus in the G.728 mode it compresses a digitized PCM (64 Kbit/s) or linear (128 Kbit/s)

voice signal into a 16 Kbit/s bit stream, and vice versa. The algorithm is implemented in

16-bit fixed point arithmetic and complies with the newest fixed point specification set

forth by the ITU.

In G.723 mode it compresses the PCM or linear voice signal into 5.3 Kbit/s (ACELP) or

6.3 Kbit/s (MP-MLQ) bit stream, and vice versa. The implementation complies with the

newest ITU-T C-code V5.1 and includes the G.723 Annex A (Voice Activity Detection

and Comfort Noise Generation).

In the G.722 mode it compresses the PCM compressed (128 Kbit/s) or the linear

uncompressed (256 Kbit/s) 7-kHz audio samples into a rate of 48/56/64 Kbit/s, and vice

versa.

The JADE finds applications in

– ISDN Videophones (H.320)

– Analog Videophones (H.324)

– Video Conference Systems

– Corporate Network voice concentrators, multiplexers and gateways

– Data-over-voice and Voice-over-data terminals.

Other potential application areas are:

– Networks (e.g. LANs) for packetized voice

– Digital Added Main-Line (DAML) & Digital Circuit Multiplication Equipment (DCME)

– Voice storage e.g. in PC based applications

– Message recording and distribution.

The interfaces of the JADE allow a seamless integration into IOM-2 based systems. After

the circuit is set up in the proper mode of operation and parameter settings are

programmed by a controlling software, the circuit runs independent of the rest of the

system. Status and control information to/from the JADE can be transferred either

inband the compressed audio data via the corresponding selected interface or outband

using an 8-bit parallel host interface.

Semiconductor Group

5

Data Sheet 1998-07-01

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