
PSB 7280
Semiconductor Group
150
Data Sheet 1998-07-01
Command Data Structure
The header of the command data packet describes the JADE operation modes in effect
for data in the next packet.
See “Commands” on page 152
below for a detailed
description of the above command words.
The packet that is transferred from the JADE to the video processor - called “status data”
- consists of eight status words followed by the appropriate number of data words for the
current speech algorithm:
Status Data Structure
The compressed data is between 0 and 160 words long depending on which of the
decoding/encoding modes is active (neutral, G.728, G.711, G.722, 8-kHz samples pass-
through or 16-kHz samples pass-through). Due to the different bit-rates of the
decoding/encoding modes for 16 kbit/s, 48 kbit/s and 56 kbit/s only two, six or seven bits
of a byte are used. The most significant bits of the byte are valid and the least significant
bits are ignored. The first byte is the most significant byte of a word.
A header bit can indicate that the current compressed data is invalid. This means that it
is not decoded and instead the sound from a previous packet is repeated. By that a
simple interpolation of the speech signal is achieved to avoid an audible click.
0
1
2
3
4
5-7
8+
Command header word
Checksum of words 2-7
Set mode
Set options
Set volume
Reserved for future expansion
Compressed data: 0, 40, 80 or 160 words
0
1
2
3
4
5
6-7
8+
Status header word
Capabilities
Mode status
Options status
Volume satus
Error conditions
Reserved for future expansion
Compressed data; 0, 40, 80 or 160 words