PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 382

• 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
Figure 20-8 Echo Cancellation with Noise Reduction (Subband Mode)
The parameter NRATT determines the maximum attenuation provided by the noise
reduction unit for frequencies with noise. Note that NRATT determines a upper limit. With
decreasing level of the background noise, the attenuation of the noise reduction unit
decreases as well.
In subband mode, if the Wiener filter is enabled and if no speech is detected at the
microphone, the Wiener filter provides attenuation of the signal from the microphone. If
noise is present at the microphone and thus the noise reduction unit changes the signal
coming from the microphone, then the additional attenuation of the Wiener filter can
cause modulations audible at the line side. Therefore, a coupling of the noise reduction
unit and the Wiener filter is provided. In case no noise is present at the near end, the
Wiener filter attenuates as programmed with the parameter SWATT:WFATT. In case
significant noise is present at the near end, the Wiener filter only attenuates so much that
the attenuation of the noise reduction plus the attenuation of the Wiener filter never
exceeds NRATT. This is controlled with two parameters:
The parameter NRUP determines the noise energy at which the coupling between the
noise reduction and the Wiener filter gets active. The parameter NRLOW determines the
noise energy at which the coupling gets inactive. This value should be lower than NRUP
in order to avoid frequent activation and deactivation, when the noise energy is around
the level of NRUP.
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