u4091bm-r ATMEL Corporation, u4091bm-r Datasheet - Page 21

• Manufacturer Part Number: u4091bm-r
• Description: Programmable Telephone Audio Processor
• Manufacturer: ATMEL Corporation

4872A–CORD–08/05
Figure 12-5. Dial Tone Detector
Figure 12-6. Background Noise Monitor
Figure 12-7. Generation of Control Voltage (CT) for Mode Switching
(TLDT)
TLDR
C
CT
CT
10 µA
I
RX
V
IN
M
I
10 µA
33 k
TX
+
-
56 k
V
M
I
FI
+
-
35 mV
V
M
+
-
I
DTD
SI
36 mV
V
M
OUT
I
4
V
B
+
-
Control
control
circuit
AFS
to mode
control
(I
I
4
3
)
Dial tone det.
(BNMT)
to
attenuators
BNMR
4
I
1 µF
1-4
U4091BM-R
21