U4089B Datasheet, PDF (7/25 Pages) ATMEL Corporation – MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT

U4089B-M
Figure 6. Basic Voice-switch System
Handset
microphone
TX
attenuation
Logarithmic
Attenuation
control
Hybrid
Line
Loud
speaker
Logarithmic
RX
attenuation
Figure 7. Integration of the Acoustic Feedback-suppression Circuit Into the Speech Circuit Environment
VB
VL
GT
INLDT
TLDT
STO
VL
ZL
-
VBG ₊
Zint
SAO
GSA
SAI
SAI TLDR
AFS
control
Max
att.
AGA
-
+ ^VBG
INLDR
RECO GR
RECIN
STI
STN
STO
7
4570A–CORD–04/03