U4091BM-RFNY19 Atmel, U4091BM-RFNY19 Datasheet - Page 17

• Manufacturer Part Number: U4091BM-RFNY19
• Description: RF Wireless Misc COM.CORDED - FEATURE PHONE CIRCUIT
• Manufacturer: Atmel
• Type: Programmable Telephone Audio Processorr

Specifications of U4091BM-RFNY19

• Operating Frequency: 100 KHz
• Operating Temperature Range: - 55 C to +150 C
• Package / Case: SSO-44
• Mounting Style: SMD/SMT

12. Acoustic Feedback Suppression
Figure 12-1. Basic System Configurations
4872B–CORD–01/11
MICRO
INLDT
CTU
RTU
MICO
LOG
SA
Acoustical feedback from the loudspeaker to the hands-free microphone may cause instability
of the system. The Atmel
offers a 4-point or (alternatively) a 2-point signal-sensing topology (see
Two attenuators (TXA and SAI) reduce the critical loop gain via the serial bus either in the
transmit or in the receive path. The overall loop gain remains constant under all operating
conditions.
The LOGs produce a logarithmically-compressed signal of the TX- and RX-envelope curve.
The AFSCON block determines whether the TX or the RX signal has to be attenuated.
The voice-switch topology can be selected by the serial bus. In 2-point-sensing mode,
AFSCON is controlled directly by the LOG outputs.
TLDT
CTLO
CBNMT
BNMT
CALCR
LOG
BNM
AFSCON
SAI
TXA
®
U4091BM-R has a very efficient feedback-suppression circuit which
control
Mode
CCT
CT
DTD
CALCT
CBNMR
LOG
BNMR
BNM
TLDR
CRLO
AGATX
LOG
Atmel U4091BM-R
CRU
RRU
RECO2
RECO1
INLDR
Figure
AGARX
HV
12-1).
STO
Line
17