1000BASE-T/100BASE-TX/10BASE-T Physical Layer Compliance Tests Manual
Intel Confidential
63
100Base-TX Receiver Return Loss
16 100Base-TX Receiver Return Loss
ANSI Section 9.2.2
16.1
Test Purpose
To measure the receiver return loss.
16.2
Specification
“The differential input impedance shall be such that the return loss is as shown below. The
requirement is specified for any reflection due to differential signals incident upon RX +/- from a
twisted pair having any impedance within the range specified in [ANSI X3.263 section] 11.1.1.
The return loss shall be maintained when the receiver circuit is powered.
Greater than 16 dB from 2 MHz to 30 mHz
Greater than (16 - 20log(
f
/30 MHz)) dB from 30 MHz to 60 MHz [where
f
= frequency]
Greater than 10 dB from 60 MHz to 80 MHz”
1
The impedance environment for the measurement of the UTP AII (Active Input Interface) return
loss shall be 100
Ω
± 15
Ω
. The impedance environment shall be nominally resistive with a
magnitude of phase angle less than 3° over the specified measurement frequency range.
16.3
Test Equipment
•
Network analyzer (50 KHz to 500 MHz range)
•
S-parameter test set (or transmission/reflection test set)
•
Host computer running gigconf.exe
16.4
Test Fixtures
•
100Base-TX balun test fixture (
•
BNC cable, with 50
Ω
characteristic impedance (
•
Network analyzer calibration fixture (
•
CAT5 twisted pair cable (under 6 inches in length)
16.5
Test Procedure
1. Turn on the network analyzer and let it warm up for five to ten minutes.
1.
ANSI X3.263-1995, p 32.