Teledyne LeCroy QPHY-ENET - Manual (Page 69)

QPHY-ENET Software Option
QPHY-ENET Operator’s Manual Rev G
69
As shown on the board, J15 and J58 connect pair A to the oscilloscope; J18 and J66 connect pair B to the
oscilloscope; J56 and J69 connect pair C to the oscilloscope and J57 and J70 connect pair D to the oscilloscope.
Install jumpers only on one of these pairs.
Common Mode Output Voltage section (C)
In this section, each side of an Ethernet signal pair is connected to a common point through a 47.5 Ω resistor.
J35, J36, J37 and J38 connect one of those common points to the two available measurement points: SMA
connector J2, and differential probe connector J79 (TP10). If the measurement is made using a high-impedance
probe at J79, then please place a jumper across J55, to provide a 50 Ω load for the common mode voltage. If
measurement is made using J2, then please remove the jumper from J55.
1000BT Template Tests section (D)
Use this section for Gigabit Ethernet Mode 1 and Mode 4 (Distortion) measurements. Both of these tests subject
the DUT to a disturbing sine wave. This section of the board is meant to allow the oscilloscope to make the
required measurements by attenuating the disturbing sine wave seen by the oscilloscope.
Pair Install Remove Pair Install Remove
A J39, J40 J43, J44, J41, J42, J45, J46 A J60, J61, J62 J59
B J43, J44 J39, J40, J41, J42, J45, J46 B J59, J60, J62 J61
C J41, J42 J39, J40, J43, J44, J45, J46 C J59, J61, J62 J60
D J45, J46 J39, J40, J41, J42, J43, J44 D J59, J60, J61 J62
Table 9. Jumper configuration for each pair measurements (connection & termination)
Connect the oscilloscope to J86 (+) and J87 (-)
Connect Disturbing Signal to J3 and J4
After establishing the above jumper configurations, you can perform the Data Path calibration, or skip to the
Disturber calibration, or skip directly to making measurements if the calibrations were previously performed. The
Disturber calibration requires a slightly different jumper configuration, which is specified in the
X
Disturber
Calibration Procedure
X
section of this manual.
Load & Probes section (F)
There are no jumpers in this section. The Test Points are connected to each Ethernet signal pair across a 100 Ω
resistive load. This section can be use for direct connection to a high impedance differential probe. We
recommend using the “Differential Return Loss” section instead, which provides a direct connection of each side
of each Ethernet signal pair to the 50 Ω termination in an oscilloscope channel via SMA cables.
Differential Return Loss section (G)
Use this section for 100Base-TX template, 100Base-TX distortion, Gigabit Ethernet “Mode 2 without TX-TCLK”
and “Mode 3 without TX-TCLK” tests. This section provides a direct connection of each side of each Ethernet
signal pair to the 50 Ω termination in an oscilloscope channel via SMA cables. To minimize cross talk when
measuring one signal pair, the signals of the other pairs should be terminated, each with a 50 Ω SMA terminator.
There are no jumpers in this section.