ucb1300 NXP Semiconductors, ucb1300 Datasheet - Page 37

• Manufacturer Part Number: ucb1300
• Description: Advanced Modem/audio Analog Front-end
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The impedance seen by the telephone line equals:
in which R
A typical transformer has 156
voltage is therefore:
2000 Jun 26
R
V
Z
i(tel)
line
line
Advanced modem/audio analog front-end
=
=
=
R
2
V
t
t
o(tel)
+
represents winding resistance of the transformer, divided by 2. Assuming R
R
R
t
t
+
+
------------------------------------------
156
R
R
o
t
156
+
+
=
------------------ -
R
R
300
600
--------- -
+
o
0
2
+
300
+
R
R
=
144
i
i
300
,
winding impedance, thus R
=
V
o(tel)
456
--------- -
600
37
o
should be 144 . The ratio of the telecom input and output
i
>> R
o
, then:
Product specification
UCB1300