xrt5897 Exar Corporation, xrt5897 Datasheet - Page 19

• Manufacturer Part Number: xrt5897
• Description: Xrt5897 -seven-channel E1 Line Interface
• Manufacturer: Exar Corporation

This may be further simplified:
Where:
Therefore:
And:
Table 6. contains the results of calculations made with these equations. The numbers show that output pulse amplitude
is within millivolts of the nominal values of 2.37V and 3.00V specified by ITU G.703 for 75W and 120W operation. Also,
the 1:2 ratio transformer provides an almost-perfect match for 75W operation, and return loss is well within the ETSI
specification for the 120W load.
R
V
V
R
I =
Return Loss = 20 log
Rev. 1.11
V
eq
o
T
s
eq
= n V
Figure 10. Equivalent Circuit
= RS
= I R
R
=
T
eq
int
R
eq
n
Vs
+ Req
2
L
+ Rs
ext
R
I
T
Table 6. Calculated Transmitter Pulse Amplitude and Return Loss
Load Resistance
R
R
T
T
-- R
+ R
R
120
L
eq
eq
75
V
(W)
eq
Pulse Amplitude
Vo (Volts Peak)
19
2.43
3.01
Return Loss (dB)
Output
31.3
13.8