Bt8370/8375/8376
2.0 Circuit Description
Fully Integrated T1/E1 Framer and Line Interface
2.9 Transmit Line Interface Unit
2.9.4.2 Return Loss
Return loss is the measure of loss in the return path due to an impedance
mismatch. To meet a –18 dB transmitter return loss, independent of the cable
type, uses a 51.1 Ω termination resistor (see Figure 2-46). To see the effect of
different termination resistors on the pulse height, see Figure 2-47.
Figure 2-46. Nominal Return Loss
Nominal Return Loss for 75, 100, 120 lines, xfmr=1:1.36
0
-10
–18 dB
-20
–31 dB
-30
-40
-50
-60
-70
-80
75
100
120
30
35
40
45
50
55
Rterm [ ]
60
65
70
75
80
N8370DSE
Conexant
2-81