ISD-T360 ETC [List of Unclassifed Manufacturers], ISD-T360 Datasheet - Page 98

• Manufacturer Part Number: ISD-T360
• Description: VoiceDSP Digital Speech Processor with Master/Slave, Full-Duplex Speakerphone, Multiple Flash and ARAM/DRAM Support
• Manufacturer: ETC [List of Unclassifed Manufacturers]

2-58
31
32
34
36
37
Index
Acoustic Echo
Canceler (AEC):
SP_AEC_PRIORITY_BIAS
Acoustic Echo
Canceler (AEC):
SP_AEC_COUPLING_
LOSS_THRESHOLD
Acoustic Echo
Canceler (AEC):
SP_AEC_LR_LEVEL
Acoustic Echo
Canceler (AEC):
SP_AEC_CLIP_POS
Acoustic Echo
Canceler (AEC):
SP_AEC_CLIP_NEG
Parameter Name
Table 2-9: TUNABLE PARAMETERS: Speakerphone
Controls the bias in priority between the Send and Receive
paths.
If send priority-bias is preferred, the value should be greater
than zero.
For no priority bias, the value should be zero.
For priority bias for the Receive path, the value should be
negative.
Steps are 3 dB each (e.g., +3 is 9 dB bias for the Send path, –2
is 6 dB bias for the Receive path).
Legal values: –4 to 4.
This parameter limits the acoustic return loss. Its value
(SP_AEC_COUPLING_LOSS_THRESHOLD / 32767) is compared
with the RMS value of S
during a single-talk event. The loop gain is decreased, if
necessary, to control the TCL level.
For SP_AEC_COUPLING_LOSS_THRESHOLD = 32767 this loop is
disabled.
Legal values: 0 to 32767.
Controls the speakerphone gain from the microphone to the
line-out. The total attenuation, or gain, depends on both of
the analog gains and this value. The gain is:
where:
Legal values: 0 to 16000.
Specifies the positive peak-value at which the analog circuit
of the line-out saturates. Codec analog full scale corresponds
to µLAW full scale values after expansion.Assume that positive
saturation occurs at amplitudes higher than those of a sine
wave at X [dBm0]. The SP_AEC_CLIP_POS value is set as:
SP_AEC_CLIP_POS = 32636 * 10
Note: a sine wave with amplitude 4 * 8159 = 32636
corresponds to 3.17 dBm0.
Example:
For X = –6.2761 dBm0, the value is:
SP_AEC_CLIP_POS = 32636 * 10
32636 =11000;
Legal values: 0 to 32767.
Specifies the negative peak value at which the analog circuit
of the line-out saturates. Codec analog full scale corresponds
to µLAW full scale values after expansion.The value of
SP_AEC_CLIP_NEG is set as shown for SP_AEC_CLIP_POS,
above.
Legal values: –32768 to 0.
K * signal
K = SP_AEC_LR_LEVEL/4096.
out
Description
divided by the RMS value of R
((X – 3.17)/20)
((–6.2761– 3.17)/20)
= 0.3371 *
Voice Solutions in Silicon™
in
,
0
2047
14000
16000
–16000
Default