PEF 20954 HT V1.1 Infineon Technologies, PEF 20954 HT V1.1 Datasheet - Page 73

• 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

Table 32
Register
AVDCI
CONFSCU
1
VDFCTRL defines the effects on the detection of a non-voice event. For stability reasons
the adaptive algorithm should be frozen (VDFCTRL. VDFRELEN), when the echo
attenuation reaches the specified level in VDFCTRL.VDFREL. Unfortunately this might
lead to a locking of the adaptive algorithm, if the SIDEC has adapted to a periodical
signal and the periodical signal changes it's frequency, or if the SIDEC has momentarily
misadapted to a periodical signal and the H-registers are frozen due to the reaching of
the specified attenuation level and the presence of the periodical signal. In order to
prevent this situation it is recommended to let the attenuation meters adapt slowly by
modifying the ADAPTFAST and ADAPTSLOW values of the CONFSCU1 register and to
set VDFCTRL. VDFREL to a high value in order to give the canceller the chance to
converge better sufficiently well before getting frozen.
The AVDDI, AVDHG and AVDCI registers define the sensitivity and speed with which
periodical signals are detected. Detection intervals longer than 64ms are not
recommended in 128 ms mode in order to keep the H-register stable on sinusoidal
signals. Be careful with sensitivity settings that are too aggressive since this might
jeopardize your convergence speed and ERLE.
Data Sheet
Addr. Value
75H
12H
Sinusoidal (non-voice) signal protection (cont’d)
VDDIFF
VDCI
ADAPTFAST
ADAPTSLOW
Mod.
Down
Up
Down
Up
Down
Up
Down
Up
Down
73
Effect
ERLE "Down", NLP, DT detection slow
ERLE "Down", NLP, DT detection slow
stability "Down", convergence speed
"Up", if activated
stability "Up", convergence speed
"Down", if activated
stability "Down", convergence speed
"Up", if activated
stability "Up", convergence speed
"Down", if activated
stability "Down", convergence speed
"Up", if activated
ERLE "Up", NLP, DT detection slow
ERLE "Up", NLP, DT detection slow
Operational Description
Rev. 2, 2004-07-28
PEB 20954
PEF 20954