PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 378

• Manufacturer Part Number: PSB21473FV13XT
• Manufacturer: Infineon Technologies

Specifications of PSB21473FV13XT

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3.135V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 144
• Lead Free Status / RoHS Status: Compliant

Data Sheet
When double talk is detected, the attenuation reported by the echo cancellation unit to
the echo suppression unit is increased. This is because the echo is less noticeable
anyway and any possible signal distortion from the echo suppression is reduced. The
parameter AECDTR determines the maximal increase of the reported attenuation during
double talk. The rate how fast the reported attenuation increase gets active after double
talk detection or inactive after the end of double talk is determined by the parameters
AECDTI and AECDTD, respectively. This is illustrated in figure 20-6 where the dashed
line shows the actual attenuation while the solid line shows the reported attenuation.
Figure 20-6 Echo Cancellation Unit - Double Talk Reduction
The attenuation of the echo suppression unit may be insufficient when the echo
cancellation unit is not yet well adapted. In case of a significant change of the
characteristics of the acoustics, the attenuation reported by the echo cancellation unit
may be too high until it discovers that it has to adapt itself again. If, in addition, double
talk reduction is in effect, then the echo suppression unit might not attenuate enough to
avoid echoes. Therefore a maximal echo attenuation reported by the echo cancellation
unit to the echo suppression unit can be programmed by the parameter AECLIM.
Example:
attenuation
10 dB
20 dB
30 dB
AEC
level
detected
double
talk
AECDTR
378
double
end of
talk
Digital Signal Processor
time
PSB 21473
2003-03-31
INCA-D