PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 159

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

6.2.2
The uncompressed data protocol is quite simple. The default configuration is 8-kHz
sampling rate and 16-bit linear data. The sampling rate can be switched between 8-kHz
and 16 kHz (see S-bit in the control block) and the data format can be selected to be
either 16-bit linear or 8-bit PCM (G.711 A-/ -law). For a 10 ms framing the size of the
uncompressed data (in bytes) is listed in Table 21:
Table 21
8-kHz sampling rate
16-kHz sampling rate
Note: Independently of the interface selection for the uncompressed audio, always the
6.2.3
In this chapter the timings and/or interrupt handshake procedures are described for the
different hardware interface selections (Host/Host, IOM/Host, IOM/Serial Audio
Interface).
After a hardware reset the firmware automatically does all necessary initializations for
the IOM/Serial Audio Interface combination described in Section 6.2.3.3. The other
interface combinations can be configured by configuring the control block (see
Section 6.2.1.1).
Note: After a hardware reset, the JADE firmware needs to initialize its internal memories
6.2.3.1
This interface combination is used for offline processing of audio (ISEL(1-0) = 00). I.e.
the compression can be done faster than realtime, because the JADE is in each mode
able to process audio at least in realtime. This definitely also depends on the capabilities
of the host processor to provide a fast interrupt service to the handshake procedure
described below. The most complex algorithm is G.728, in this mode the maximum
possible speed is only slightly faster than realtime, because almost all of the
computational power of the JADE is needed to compress the audio.
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most significant bit of the most significant byte is transferred first, e.g. 16-bit linear
samples are split up into two bytes and the most significant bit of the most
significant byte is transferred first (big endian).
and interfaces. The time to do this is less than 10 ms. The user must take care to
access the JADE only after this initialization phase is completed, i.e. 10 ms after
the hardware reset.
Uncompressed Data Protocol
Audio Interface Timings
Uncompressed Data: Host IF, Compressed Data: Host IF
16-bit Linear
160
320
159
G.711 A-/ -law
80
160
Data Sheet 1998-07-01
Firmware Features
PSB 7238