PEB3265 Infineon Technologies Corporation, PEB3265 Datasheet - Page 69

• Manufacturer Part Number: PEB3265
• Description: (PEB326x / PEB426x) Dual Channel Slicofi-2 / Slic Duslic
• Manufacturer: Infineon Technologies Corporation

Preliminary
3.8.3
The DuSLIC contains an adaptive line echo cancellation unit for the cancellation of near
end echoes. With the adaptive balancing of the LEC unit the Transhybrid Loss can be
improved up to a value of about 50 dB. The maximum echo cancellation time selectable
is 8 ms. The line echo cancellation unit is especially useful in combination with the DTMF
detection unit. In critical situations the performance of the DTMF detection can be
improved.
If 8 ms line echo cancellation length (LEC Length) is used, please take care about the
MIPS requirements described in
The DuSLIC line echo canceller is compatible with applicable standards ITU-T G.165
and G.168. An echo cancellation delay time of up to 8 ms can be programmed.
The LEC unit consists basically of an FIR filter, a shadow FIR filter, and a coefficient
adaption mechanism between these two filters as shown in
Figure 34
The adaption process is controlled by the three parameters Pow
Level Receive), DeltaP
on Page
1. S
2. S
With the first condition, adaptation to small signals can be avoided. The second condition
avoids adaptation during double talk. The parameter DeltaP
provided by external circuitry.
Data Sheet
LEC,R
LEC,R
S
LEC, TIN
228). Adaptation takes place only if both of the following conditions hold:
> Pow
– S
Line Echo Cancelling (LEC) (only DuSLIC-E/-E2/-P)
LEC,TIN
Line Echo Cancelling Unit - Block Diagram
LECR
Shadow
> DeltaP
Filter
FIR
LEC
(Delta Power) and DeltaQ (Delta Quality)
LEC
Chapter
Adapt
Coeff.
3.8.5.
69
Coeff.
Copy
LEC
Figure
Filter
Functional Description
represents the echo loss
FIR
S
LECR
DuSLIC_0004_LECunit.emf
LEC,R
34.
(“POP Command”
(Power Detection
S
LEC, TOUT
2000-07-14
DuSLIC