ZXDSL 9210 (V3.1) Broadband Universal Access Equipment Technical Manual
3-8
2. 100M Ethernet interface parameters
1) Transmitter
interface
parameters
z
Differential mode output voltage of transmitter
Differential mode output voltage is the difference between the voltages at both
ends of a balanced circuit. The differential mode output voltage of a transmitter
is the voltage difference between TD+ and TD- of a differential line pair. The
indices of the transmitter differential mode output voltage of the 100M Ethernet
interface are as follows:
STP: 1,165 mV
≤
Vout
≤
1,285 mV
UTP: 950 mV
≤
Vout
≤
1,050 mV
z
Signal amplitude symmetry
Signal amplitude symmetry is the ratio of the absolute value of +Vout to that of
-Vout. The index of transmitter differential mode output voltage of the 100M
Ethernet interface is:
-Vout
+Vout
0.98¡ Ü
¡ Ü
1.02
z
Impedance feedback loss
Impedance feedback loss reflects impedance match. The calculation formula is:
Xr=20lg| (Z+R)/(Z-R)|; Z is the actual resistance while R is the nominal
resistance. The nominal impedance of UTP is 100
Ω
and that of STP is 150
Ω
.
The impedance feedback loss of the 100M Ethernet interface at 2.0 to 80 MHz
meets the following requirements:
2 to 30 MHz: > 16 dB
30 to 60 MHz: > 16 – 20 log (f/30) dB f: frequency (MHz)
60 to 80 MHz: > 10 dB
z
Signal edge rise/fall time
Rise edge is defined as the time required for the baseline voltage (generally 0) to
rise up to stable value +Vout or -Vout in case of signal transient. Fall edge is
defined as the time required for +Vout or -Vout to fall down to the baseline
