TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
9.15.2
AEC Tail Length
The CT8022 supports programmable AEC Tail Length up to 30ms. The maximum available Tail-Length depends on
which other features of the CT8022 are active as shown in the following table:
CT8022 Operating Mode
Maximum AEC Tail-Length
Milliseconds
AEC Filter
Taps
Full Duplex TrueSpeech 6.3, 5.3, 4.8, 4.1 (G.723.1) with DTMF Detection and
Call Progress Tone Detection
TrueSpeech 8.5 (external) with DTMF Detection and Call Progress Tone
Detection
30
30
30
240
240
240
Standalone Speakerphone Mode
Each AEC Filter Tap is equivalent to 125 microseconds of Tail Length (at 8.0 KHz).
The AEC Tail Length is programmable in units of 2ms or 16 Taps.
It is possible to change the AEC Tail Length only when the CT8022 is in IDLE mode and the AEC is switched Off.
To program the AEC Tail Length use the command:
Command:
Status:
B0X0H
B0X0H
Where X0H is the AEC Tail Length in Taps:
B050H
B0A0H
B0F0H
Selects 10ms, 80 Taps
Selects 20ms, 160 Taps
Selects 30ms, 240 Taps
The default AEC Tail Length is 10ms, 80 Taps
102
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 ]
