
PSB 7280
Semiconductor Group
19
Data Sheet 1998-07-01
standards, so that compatibility between equipment from different manufacturers is
ensured.
A low-cost H.320 videophone solution for ISDN line as a PCI card for commercial PC’s
is shown in
Figure 5
.
Figure 5
The JADE 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 compresses/decompresses audio according to the ITU-T standards G.728,
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 has all its memories
on chip, no external SRAM needs to be connected.
The ARCOFI-SP (Audio Ringing Codec Filter) is a hands-free codec for 3.1-kHz voice
which performs detection and elaborate balancing of the received and transmitted audio
to suppress undesirable effects due to acoustical feedback of the signal from the remote
subscriber. The quality obtained is very close to that of echo-free full duplex
conferencing.
IOM-2
Host
Video in
SRAM
Video
Capture
SRAM/DRAM
Video out
PAL/NTSC
Camera
ISDN
JADE
SIEMENS
PSB 7280
ISAC-S TE
SIEMENS
PSB 2186
SIEMENS
SAB 83C515A
ARCOFI-SP
SIEMENS
PSB 2163
Stereo DAC
MPEG 1
PCI
Bus Interface
Video
Codec