TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
9.22
Host-to-Host Data Compression and Decompression
The CT8022 can be operated as a full or half-duplex TrueSpeech compression engine in a CODEC-less
configuration. In this situation, the CT8022 routes the uncompressed data stream to the Host instead of to the
CODEC.
Host Interface
[2]
[1]
[4]
[3]
Frame
Buffering
Frame
Buffering
TrueSpeech
Encoder
TrueSpeech
Decoder
Figure 9-6:
Host-to-Host Operation
The Host-to-Host compression/decompression protocol is structured so that the four data exchange operations are
independent. The four data exchange operations that take place are:
1. Uncompressed 16-bit linear data transfer from Host to CT8022, denoted using [1] in the following explanations.
2. Compressed TrueSpeech data transfer from CT8022 to Host, denoted using [2] in the following explanations.
3. Compressed TrueSpeech data transfer from Host to CT8022, denoted using [3] in the following explanations.
4. UnCompressed 16-bit linear data transfer from CT8022 to Host, denoted using [4] in the following explanations.
The compressed data exchanges, [2] and [3] to and from the CT8022 internal Frame Buffers take place using the
same transfer protocol as used for record and playback (TFR Mode = 00). The Host should ensure that the AEC
(Acoustic Echo Canceller) state is set to Off for Host-to-Host operation.
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DSP GROUP, INC., 3120 SCOTT BOULEVARD CT8022A11AQC FW Revision 0118
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
All specifications are subject to change without prior notice.
ETC [ ETC ]
