PBL386151 Ericsson, PBL386151 Datasheet - Page 10

• Manufacturer Part Number: PBL386151
• Description: Subscriber Line Interface Circuit
• Manufacturer: Ericsson

PBL 386 15/1
General
A simplified AC model of the transmission
circuits is shown in figure 9. Circuit analysis
yields:
where:
V
V
E
I
R
G
Z
Z
Z
10
Figure 9. Simplified AC transmission circuit.
Functional Description and Applications
Information Transmission
L
L
T
RX
TX
TR
L
F
V
V
Z
V
2-4S
T
TR
TX
TR
=
+
= I
is a ground referenced version
of the ac metallic voltage
between the TIPX and RINGX
terminals.
is the ac metallic voltage
between tip and ring.
is the line open circuit ac metallic
voltage.
is the ac metallic current.
is a fuse resistor.
is the SLIC two-wire to four-
wire gain (transmit direction) with
a nominal value of -0.5.
(phase shift 180 .)
is the line impedance.
determines the SLIC TIPX to
RINGX impedance for signal in
the 0 - 20kHz frequency range.
controls four- to two-wire gain.
V
Z
L
G
RX
RX
V
•
2-4S
Z
TX
=
L
- E
- I
I
L
RSN
L
L
•
2R
F
+
-
V
TR
Z
(1)
(2)
(3)
L
RING
TIP
+
-
E
Z
TR
L
R
R
F
F
RINGX
TIPX
V
R
Two-Wire Impedance
To calculate Z
to the two-wire line by the SLIC including
the fuse resistor R
Two-Wire to Four-Wire Gain
From (1) and (2) with V
RX
HP
RSN
From (1) and (2):
Z
Thus with Z
Z
G
TR
T
2-4
=
=
PBL 386 15/1
=
is the analogue ground referenced
receive signal.
is the receive summing node
current to metallic loop current
gain. The nominal value of
Internal resistor appprox. 180 k
V
V
RSN
RSN
TX
TR
RSN
R
HP
•
=
Z
= 400
G
TR
T
•
TR
G
2-4S
, G
, the impedance presented
2-4S
RSN
+
-
2-4S
G
•
F
, let V
(2R
2-4S
Z
Z
,
•
T
- 2R
T
G
/
RSN
F
RX
2-4S
- |Z
RSN
RX
F
= 0:
, and R
= 0.
- 2R
TR
|)
F
F
known:
I
L
/
I
I
L
L
RSN
VTX
RSN
Four-Wire to Two-Wire Gain
From (1), (2) and (3) with E
In applications where
2R
to Z
Four-Wire to Four-Wire Gain
From (1), (2) and (3) with E
G
G
G
F
Z
4-2
4-2
4-4
L
T
- Z
, the expression for G
Z
RX
=
= -
=
T
/(
V
V
V
V
RX
RX
TR
TX
Z
Z
RSN
T
RX
=
=
+
-
+
-
•
Z
Z
•
Z
Z
V
V
G
2
T
TX
T
RX
RX
RX
2-4S
•
•
•
1
G
Z
Z
) is chosen to be equal
2-4S
RSN
RSN
G
T
T
2-4S
- G
- G
Z
•
4-2
2-4S
2-4S
( Z
L
L
L
= 0:
= 0:
simplifies to:
L
•
•
+ 2R
( Z
( Z
L
L
+ 2R
+ 2R
F
)
F
F
)
)