PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 385

• 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

The Attenuation Control performs the switching between the three possible states by
using the attenuation stages GHX and GHR. Actually, state switching is controlled by the
speech comparators SCAS and SCLS and by the speech detectors SDX and SDR. The
gain control units AGCX, AGCR, LGAX, and LGAR are used to achieve proper signal
levels for each state.
All blocks are programmable. Thus, the telephone set can be optimized and adjusted to
the particular geometrical and acoustical environment. The following sections discuss
the blocks of the echo suppression unit in detail.
20.1.3.1 Speech Detector
For each signal source a speech detector (SDX, SDR) is available. The speech
detectors are identical but can be programmed individually. Figure 20-12 shows the
signal flow graph of a speech detector.
Figure 20-12 Speech Detector - Block Diagram
The first three units (LIM, LP1, PD) are used for preprocessing the signal while the actual
speech detection is performed by the background noise monitor.
Background Noise Monitor
The tasks of the noise monitor are to differentiate voice signals from background noise,
even if it exceeds the voice level, and to recognize voice signals without any delay.
Therefore the Background Noise Monitor consists of the Low-Pass Filter 2 (LP2) and the
offset in two separate branches. Basically it works on the burst-characteristic of the
Data Sheet
LIM
LIM
Signal Preprocessing
LP1
LP1
PD
PDS
PDN
385
Background Noise Monitor
LP2
Digital Signal Processor
LP2S
LP2N
LP2L
OFF
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PSB 21473
2003-03-31
INCA-D