PBL 387 71
Parameter
Four-wire to longitudinal balance, B
FLE
E
B
FLE
= 20 × Log
RX
V
Lo
Two-wire return
loss
, r
|Z
+ Z
L
|
r = 20 × Log
TRX
|Z
TRX
– Z
L
|
TIPX idle voltage, V
TI
RINGX idle voltage, V
RI
Open loop voltage, |V
TR Open
|
Ref
fig
4
Conditions
active state
0.2 kHz < f < 3.4 kHz
0.2 kHz < f < 0.5 kHz
0.5 kHz < f < 1.0 kHz
1.0 kHz < f < 3.4 kHz, Note 3
active normal, I
L
= 0
active normal, I
L
= 0
active, I
L
= 0
43
25
27
23
- 0.9
- 51
50
56
dB
dB
dB
V
V
V
Min
40
Typ
58
Max
Unit
dB
Four-wire transmit port
(VTX)
Overload level, V
TXO
Off-hook, I
L
≥
10mA
On-hook, I
L
≤
5mA
Output offset voltage,
∆V
TX
Output impedance, Z
TX
0.2 kHz < f < 3.4 kHz
5
Load impedance > 20 kΩ,
Load impedance > 20 kΩ,
1% THD, Note 4
0.5
0.5
-100
5
100
20
V
Peak
V
Peak
mV
Ω
Four-wire receive port
(receive summing node = RSN)
RSN dc offset voltage, V
RSNdc
RSN impedance
RSN current, I
RSN
, to metallic loop
current ,I
L
, gain,
α
RSN
I
RSN
= 0 mA
0.2 kHz < f < 3.4 kHz
0.3 kHz < f < 3.4 kHz
-25
10
400
25
50
mV
Ω
ratio
TIPX
C
V
Lo
R
LT
V
TR
R
LR
VTX
R
T
1
<< 150Ω, R
LT
= R
LR
= 300Ω
ωC
E
RX
PBL 387 71
RINGX
RSN
R
T
= 120kΩ,
R
RX
= 120kΩ
R
RX
Figure 4. Metallic to longitudinal, B
MLE
and four-wire to longitudinal balance, B
FLE
.
C
R
L
I
Ldc
E
L
TIPX
VTX
R
T
V
TXO
1
<< R
L
, R
L
= 600Ω
ωC
R
T
= 120kΩ,
R
RX
= 120kΩ
PBL 387 71
RINGX
RSN
R
RX
Figure 5. Overload level, V
TXO
, four-wire transmit port.
4
EN/LZT 146 135 R1A © Ericsson Microelectronics, December 2001
ERICSSON [ ERICSSON ]
