PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 5

• Manufacturer Part Number: PSB7238
• Description: Joint Audio Decoder-Encoder - Multimode
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

1
1.1
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
Introduction
Overview
5
Data Sheet 1998-07-01
Introduction
PSB 7238