PBL 388 12
Figure 7. Transmitter channel input
amplifier used to suppress ripple in the
mic. supply. (CMRR).
R1 = R2
≈
3k
R3 = R4
≈
100k
R5 = R6
C1 = C2
+
F
2
Ref.
R4
R3
R7
R6
C2
-
R2
2
R5
C4
Mic.
C1
C3
3
R1
F
1
+
16
Figure 8. Transmitter and receiver
channel rectifier characteristics.
V
RxDet
+600
+400
+200
V
ref
≈
2V
V
ref
-200
2.5
0.5
5.0
7.5
1.0
10
1.5
V
Rx in
m
V
p
V
Tx in
-400
-600
V
TxDet
Figure 9. Relationship in timing between
the voltage levels at Tx
In
, Tx
Det
and N
Det
Txin
TxDetout
N Det
Figure 10. Transmitter and receiver
channel output dynamics.
500
V
Txout
(mV)
V
Rxout
(mV)
500
400
400
300
300
200
200
100
100
≈
2.4
2.6
2.8
3.0
3.2
3.4
≈
V+ (V)
V+ (V)
2.4
2.6
2.8
3.0
3.2
3.4
7