PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 149

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

d
e
Re(1-0),
Rd(1-0)
S
Semiconductor Group
decoding mute enable (1) and disable (0). After switching, a ramping function
is implemented to avoid audible clicks
encoding mute enable (1) and disable (0). After switching, a ramping function
is implemented to avoid audible clicks
Restricted number of bits for encode and decode. Only used for G.722, that
offers modes where less than 8 bits per byte are used: 7 bits per byte
(56 Kbit/s) and 6 bits per byte (48 Kbit/s).
00
01
10
11
G.723 uses these bits in a different way. When the encode mode is G.723
the Re bits give the desired encoding method:
00
01
10
11
Rd is the same as the above, but indicates the mode of the data in this
packet. It is the same as the corresponding bits of the G.723 packet data.
Sampling Rate of the codec connected to the JADE, either 8 kHz (0) or
16 kHz (1). If the sampling rate of the codec is different from the sampling
rate expected by the selected speech coder, the JADE automatically uses
over-/undersampling filters to convert the audio data.
When using G.728 mode and S = 1 indicating a 16-kHz codec is connected,
the postfilter of G.728 is switched off to ensure the computational power for
the over-/undersampling filters is available. The effect on the audio quality is
negligible.
When using G.722 mode and S = 0 indicating an 8-kHz codec is connected,
the bandwidth of the G.722 input/output data is reduced to 3.4 kHz.
Nevertheless, the compressed data stream is fully compatible and
interoperable with the G.722 standard.
8 valid bits per byte
7 valid bits per byte
6 valid bits per byte
Reserved
High rate, don’t use silence suppression
High rate, use silence suppression
Low rate, don’t use silence suppresion
Low rate, use silence suppression
149
Data Sheet 1998-07-01
Firmware Features
PSB 7238