PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 19

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

In order to make the best possible use of the total bandwidth and obtain the best possible
video quality, the audio should require only a small fraction of the total data rate. This is
made possible by using parametric compression techniques such as LD-CELP
(16 Kbit/s), ACELP (5.3 Kbit/s) or MP-MLQ (6.3 Kbit/s). Above all, the corresponding
norms (G.728 and G.723) are internationally adopted standards, so that compatibility
between equipment from different manufacturers is ensured.
A low-cost H.320/324 videophone solution for both ISDN and POTS line as a PCI card
for commercial PC’s is shown in Figure 5.
Figure 5
This “multimode” board is capable to work with whatever telephone line is available,
digital ISDN or analog POTS.
The JADE MM and the video codec chip (e.g. the Video Communication Processor
“VCP” from 8 8 Inc.) constitute the heart of the videophone.
Both (together with the microcontroller 83C515) are connected to the PC via the PCI bus
using PCI bus interface (e.g. the “VPIC” of 8 8 Inc.).
The JADE MM compresses/decompresses audio according to the ITU-T standards
G.728, G.723, G.722 and G.711 and runs a fully inband controlled protocol on the
interface to the video codec. It receives/transmits uncompressed audio via the IOM-2
interface from/to the ARCOFI-SP. The setup for this application is done automatically
after a hardware reset, so no additional initialization by a host is required. Since the
JADE MM has all its memories on chip, no external SRAM needs to be connected.
Semiconductor Group
PAL/NTSC
Camera
SRAM/DRAM
Stereo DAC
Capture
SIEMENS
ARCOFI-SP
Video
PSB 2163
MPEG 1
Video in
PCI Bus
Video out
Bus Interface
PCI
Codec
Video
SRAM
IOM-2
19
Host
SIEMENS
JADE MM
PSB 7238
(synchronous access)
V.34 Modem
........
SIEMENS
SAB 83C515A
SIEMENS
ISAC-S TE
PSB 2186
Data Sheet 1998-07-01
Introduction
PSB 7238
POTS
ISDN