PEF 20954 HT V1.1 Infineon Technologies, PEF 20954 HT V1.1 Datasheet - Page 68

• Manufacturer Part Number: PEF 20954 HT V1.1
• Description: IC ECHO CANCELLER DGTL TQFP144
• Manufacturer: Infineon Technologies

Specifications of PEF 20954 HT V1.1

• Function: Smart Integrated Digital Echo Canceller (SIDEC)
• Interface: PCM, Serial, UCC
• Number Of Circuits: 1
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 350mA
• Power (watts): 900mW
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 144-LFQFP
• Includes: Double Talk Detection
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: PEF20954HTV1.1; SP000007505

4.3.4
4.3.4.1
A configurable damping feature of main and auxiliary coefficients increases the
algorithmical stability even further, thus preventing possible divergence even in difficult
situation.
4.3.4.2
In order to prevent misadaptation or sudden divergence the auxiliary coefficients can be
monitored for conspicuous patterns and the main filter adaptation limited to smaller step
sizes.
4.3.4.3
In order to prevent possible divergence or misadaptation due to the presence of a
(dominant) periodical signal (an unfortunate vulnerability inherent to all LMS algorithms)
a flexible non-voice detector is built in to SIDEC.
4.3.4.4
SIDEC can detect if it produces more echo than it receives and control the adaptive
algorithm accordingly.
4.3.4.5
Low frequency (sawtooth) or DC components can be superimposed to the receive in
signal in order to increase the stability or even the adaptability to certain waveforms. This
is a legacy feature and no longer needed for the adaptive step range algorithm.
4.3.5
SIDEC has a unique highly confiogurable and flexible non linear processing capability
that is highly integrated with adaptive filter functionality in order to suppress any
noticeable residual echo in the case of no near end voice activity.
4.3.5.1
A quite elaborate and configurable function constantly monitors the near end
background noise level.
4.3.5.2
SIDEC implements the ITU required NLP noise insertion settings plus one additional
subjectively superior noise function with configurable adaptive signal levels.
Data Sheet
Stability / divergence protection
Coefficient damping
Auxiliary coefficient supervision
Sinusoidal (non-voice) signal protection
Overcompensation protection
Low frequency RI superimposing
Non linear processing
Background noise measurement
Background noise insertion
68
Operational Description
Rev. 2, 2004-07-28
PEB 20954
PEF 20954