LeCroy Ethernet Package User manual

Ethernet
Package

For LeCroy Oscilloscopes

Operator’s Manual

November 2001

LeCroy Corporation

700 Chestnut Ridge Road
Chestnut Ridge, NY 10977-6499
Tel: [phone]

Fax: [phone]

Internet: www.lecroy.com

© 2001 by LeCroy Corp. All rights reserved. Information in this publication supersedes all earlier versions. Specifications subject to
change.

LeCroy, ProBus, and SMART Trigger are registered trademarks of LeCroy Corporation. ActiveDSO, ScopeExplorer, and Waverunner are
trademarks of LeCroy Corporation. MATLAB is a registered trademark of The MathWorks, Inc. Excel and PowerPoint are registered
trademarks of Microsoft Corporation.

ETHERNET-OM-E Rev A 1101

Chapter 1 — Overview

Chapter 2 — Operation

Contents

Introduction..................................................................................................1-1

What Is Ethernet? ................................................................................1-1

The History of Ethernet.......................................................................1-1

1000Base-T Theory of Operation.....................................................1-4

Introduction to LeCroy’s Ethernet Package....................................1-6

Getting Started............................................................................................2-1

Differential Output Templates.................................................................2-4

Select a Point To Be Tested.....................................................................2-6

Peak Differential Output Voltage and Level Accuracy......................2-8

Maximum Output Droop............................................................................2-10

Test Modes 2 and 3....................................................................................2-12

Operation Mode...........................................................................................2-14

Jitter Measurements in Master and Slave Modes .........................2-14

Setup ...................................................................................................... 2-15

Jitter in Master Mode...........................................................................2-15

Jitter in Slave Mode..............................................................................2-17

Transmitter Distortion Measurement....................................................2-18

100Base-TX..................................................................................................2-20

Mask Testing...............................................................................................2-22

Signal Measurements...............................................................................2-24

Jitter Measurements.................................................................................2-26

Chapter 3 — Remote Commands

DEFINE, DEF...................................................................................................3-1

ENET_AVG, ENAV ........................................................................................3-2

ENET_AVG_COUNT.....................................................................................3-3

PARAMETER_CUSTOM, PACU.................................................................3-4

Chapter 4 — Specifications

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Ethernet Package

iv ISSUED: November 2001 ETHERNET-OM-E Rev A

1

Introduction

What is Ethernet?

The History of Ethernet

Overview

Etherent, is the most dominant local area network (LAN)
technology. The most familiar version of Ethernet supports a data
transmission rate of 10 Mbps. More advanced versions of Ethernet
called "Fast Ethernet" and "Gigabit Ethernet" support data rates of
100 Mbps and (1000 Mbps). An Ethernet LAN may use coaxial
cable, special grades of twisted pair wiring, or fiber optic cable.
"Bus" and "Star" wiring configurations are supported. Ethernet
devices compete for access to the network using a protocol called
Carrier Sense Multiple Access with Collision Detection
(CSMA/CD).

The first experimental Ethernet system was developed in the early
1970s by Dr. Robert Metcalfe and David Boggs of the Xerox Palo
Alto Research Center (PARC). It interconnected Xerox Palo Alto
computers and printers at a data transmission rate of 2.94 Mbps.
This data rate was chosen because it was derived from the local
system clock (of the Alto computer). In July 1976, Metcalfe and
Boggs published their landmark paper entitled "Ethernet:
Distributed Packet Switching for Local Computer Networks" in the
Communications of the Association for Computing Machinery
(ACM). US Patent number 4,063,220, "Multiunit data
communications system with collision detection," was issued to
Xerox Corporation on December 13, 1977.

In 1979, Digital Equipment Corporation (DEC), Intel, and Xerox
joined for the purpose of standardizing an Ethernet system that
any company could use. In September 1980 the three companies
released Version 1.0 of the first Ethernet specification called the
"Ethernet Blue Book," or "DIX standard" (after the initials of the
three companies). It defined the "thick" Ethernet system
(10Base5), based on a 10 Mbps CSMA/CD (Carrier Sense
Multiple Access with Collision Detection) protocol. It is known as
"thick" Ethernet because of the thick coaxial cable used to
connect devices on the network. The first Ethernet controller
boards based on the DIX standard became available about 1982.
The second and final version of the DIX standard, Version 2.0, was
released in November 1982.

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Ethernet Package

In 1983, the Institute of Electrical and Electronic Engineers (IEEE)
released the first IEEE standard for Ethernet technology. It was
developed by the 802.3 Working Group of the IEEE 802
Committee. The formal title of the standard was IEEE 802.3

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Access Method and Physical Layer Specifications . IEEE reworked

some portions of the DIX standard, especially in the area of the
frame format definition. However the 802.3 standard was defined in
a manner that permitted hardware based on the two standards to
interoperate on the same Ethernet LAN.

In 1985, IEEE 802.3a defined a second version of Ethernet called
"thin" Ethernet, "cheapernet," or 10Base2. It used a thinner,
cheaper coaxial cable that simplified the cabling of the network.
Although both the thick and thin systems provided a network with
excellent performance, they utilized a bus topology, which made
implementing changes in the network difficult, and also left much
to be desired in regard to reliability. Also released in 1985 was the
IEEE 802.3b 10Broad36 standard that defined transmission of
10 Mbps Ethernet over a "broadband" cable system.

In 1987, two more standards were released. The IEEE 802.3d
standard defined the Fiber Optic Inter-Repeater Link (FOIRL) that
used two fiber optic cables to extend the maximum distance
between 10 Mbps Ethernet repeaters to 1000 meters. IEEE

802.3e defined a "1 Mbps" Ethernet standard based on twisted
pair wiring. This 1 Mbps standard was never widely used.

In 1990, a major advance in Ethernet standards came with
introduction of the IEEE 802.3i 10Base-T standard. It permitted
10 Mbps Ethernet to operate over simple Category 3 Unshielded
Twisted Pair (UTP) cable. The widespread use of UTP cabling in
existing buildings created a high demand for 10Base-T technology.
10Base-T also permitted the network to be wired in a "star"
topology that made it much easier to install, manage, and
troubleshoot. These advantages led to a vast expansion in the use
of Ethernet.

In 1993, the IEEE 802.3j standard for 10Base-F (FP, FB, & FL)
was released which permitted attachment over longer distances
(2000 meters) via two fiber optic cables. This standard updated
and expanded the earlier FOIRL standard.

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Overview

In 1995, IEEE improved the performance of Ethernet technology by
a factor of 10 when it released the 100 Mbps 802.3u 100Base-T
standard. This version of Ethernet is commonly known as "Fast
Ethernet." Three media types were supported: 1) 100Base-TX
operates over two pair of category 5 twisted pair cable; 2)
100Base-T4 operates over four pairs of category 3 twisted pair
cable; and 3) 100Base-FX operates over two multi-mode fibers.

In 1997, the IEEE 802.3x standard became available, which
marked a departure from the traditional approach by defining a
"full-duplex" Ethernet operation for the first time. Full-Duplex
Ethernet bypasses the normal CSMA/CD protocol to allow two
stations to communicate over a point to point link. It effectively
doubles the transfer rate by allowing each station to concurrently
transmit and receive separate data streams. For example, a 10
Mbps full-duplex Ethernet station can transmit one 10 Mbps
stream at the same time it receives a separate 10 Mbps stream.
This provides an overall data transfer rate of 20 Mbps. The full­duplex protocol extends to 100 Mbps Ethernet and beyond. Also
released in 1997 was the IEEE 802.3y 100Base-T2 standard for
100 Mbps operation over two pairs of Category 3 balanced cabling.

In 1998, IEEE once again improved the performance of Ethernet
technology by a factor of 10 when it released the 1 Gb/s 802.3z
1000Base-X standard. This version of Ethernet is commonly
known as "Gigabit Ethernet." Three media types are supported: 1)
1000Base-SX operates with a 850 nm laser over multi-mode fiber;

2) 1000Base-LX operates with a 1300 nm laser over single and
multi-mode fiber; and 3) 1000Base-CX operates over short-haul
copper "twinax" shielded twisted pair (STP) cable. Also released
in 1998 was the IEEE 802.3ac standard that defines extensions to
support Virtual LAN (VLAN) tagging on Ethernet networks.

In 1999, the release of the 802.3ab 1000Base-T standard defined
1 Gb/s operation over four pairs of category 5 UTP cabling:

ETHERNET-OM-E Rev A ISSUED: November 2001 1–3

1000Base-T Theory of Operation

Ethernet Package

When working on the 1000Base-T standard, the 802.3ab
committee was faced with a big challenge. Transmitting and
receiving 1000 Mbps at dual (full) duplex over the popular CAT 5­cable infrastructure is not an easy task. (Operation is over four­pair, 100 ohm Category 5 balanced copper cabling, as defined by
ANSI/TIA/EIA-568-A).

The problems were many:

? Signal attenuation
? Echo
? Return loss
? Crosstalk (NEXT, FEXT)
? Electromagnetic emissions and susceptibility (See figure

below.)

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Overview

The principles of the solution proposed by the committee were:
? Use existing 4-pair Category 5 cable. To ensure proper

operation at full link lengths, the cable must conform to the
requirements of ANSI/TIA/EIA-568-A (1995).

? Use all four pairs in the cable to keep symbol rate at 125

Mbaud (same as 100Base-TX).

? Use PAM-5 coding to increase the amount of information sent

with each symbol.

? Use 4D 8-state Trellis Forward Error Correction coding to

offset the impact of noise and crosstalk.

? Use pulse-shaping techniques to condition the transmitted

spectrum.

? Use state-of-the-art DSP signal equalization techniques to

manage the problems of noise, echo, and crosstalk; and to
ensure a bit error rate of at least 10

These principles were based on experience with the well-proven
100Base-TX, 100Base-T4, and 100Base-T2 technologies:

? 100Base-TX demonstrates that it is possible to send a symbol

stream over Category 5 cable at 125 Mbaud.

? 100Base-T4 demonstrates techniques for sending multi-level

coded symbols over four pairs.

? 100Base-T2 demonstrates the use of digital signal processing

(DSP), five-level coding, and simultaneous two-way data
streams while dealing with alien signals in adjacent pairs.

--10.

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Ethernet Package

+1V

+0.5V

0

-0.5V

-1V

Example of the 4D-PAM5 signal, used in 1000Base-T. This
diagram simplifies the signal and shows it only on one pair.
The transmission is done on four pairs in parallel.

The solution, though meeting the above criteria, is relatively
complicated. The PHY element is a DSP-based complex device.

The testing of the Physical Layer signals is also far from simple
and requires several steps.

The standard describes the testing process in detail.

Introduction to LeCroy’s Ethernet Package

As the Ethernet connection evolved over the years from one stage
to another, it kept some characteristics unchanged, such as frame
formats. Other parts, however, kept changing constantly. Among
these are the Physical Layer specifications. 10Base-T, for
example, uses 2 level Manchester encoding; 100Base-T uses 3
level MLT-3 signaling, while Gigabit (1000Base-T) uses 4D-PAM5,
based on 5 level signals. Therefore, while the evolution seemed
natural and easily implemented by the network manager, hardware
designers and manufacturers alike found it more complicated.
Actually, much more complicated, as in the case of 1000Base-T

LeCroy's Ethernet package bridges the gap between the different
testing methods for 100 and 1000 Mbps. It is based on a software
package that can be installed on DSOs with 1 GHz bandwidth or
higher. The result is a user-friendly solution that dramatically
reduces testing times and simplifies the testing process. Tests
and calculations are performed inside the DSO, bypassing the

8nsec

-1

8nsec

+1

8nsec

-1

+2

0

-2

0

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Overview

need for external programs (such as MATLAB) and making the
use of analog filters unnecessary.

You can select between 100Base-TX and 1000Base-T. Each
standard has a specific array of tests to be performed. After
selecting a test, waveforms are displayed on the DSO grid(s) while
the measurement results are listed below. Some measurements
include statistics.

The package can be easily customized, by adding new masks
(PolyMasks). The DSO can perform other tasks in parallel, and
unused channels may be used for more testing.

Ethernet Standards

Two Ethernet connections are addressed with LeCroy Ethernet
Package:

? 100Base-TX
? 1000Base-T

They are included in the IEEE 802.3 - 2000 standard.

# # #

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Ethernet Package

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2

Operation

Getting Started

Operation

Access the Ethernet Package by pressing the ANALYSIS PACKAGES
button (MATH on LC scopes). A menu showing all the packages
installed on the DSO is displayed.

Select Ethernet Analysis. The menu at left is displayed:
(If only the Ethernet Package is installed, this menu will be displayed

instantly when you press the ANALYSIS PACKAGES button).

Select the standard by pressing the corresponding soft key.
The following tests and measurements are available for

1000Base-T:

Test Mode Test or measurement to be performed Use Test

Fixture

1

2 Jitter in master mode 4
3 Jitter in slave mode 4
4 Transmitter distortion measurement 3

Peak differential output voltage and level
accuracy

Maximum output voltage droop 2
Differential output templates 1

1

ETHERNET-OM-E Rev A ISSUED: November 2001 2–1

Ethernet Package

The above menu selects one of the four test modes. In this example,
Test Mode 1 was selected.

The same menu allows the selection of input source: either a
differential probe such as AP034 (or equivalent, with 1 GHz
bandwidth minimum), or two single-ended probes with 1 GHz
minimum bandwidth (HFP1000 for example).

If probing is performed directly with two cables (using scope
channels 2 and 3) they should be coupled to 50 ? DC.

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Operation

Figure 1. Waveform generated by the DUT in Test
Mode 1. The circled letters are for reference only and are not
displayed on the screen.

Three tests, based on the above waveform are performed. The
standard specifies a disturbing signal (Vd), which has to be added to
the waveform. The setup is shown in Figure 2.

Differential Output Templates

M

In these tests, points A, B, C, D, F and H are compared against two
mask templates. The point to be tested can be selected from the
menu. This test is performed with test fixture 1 setup. The disturbing
signal is automatically removed from the composite signal inside the

(

on LC scopes)

ATH

Ethernet Package

ETHERNET PACKAGE

oscilloscope.

Figure 2. Transmitter Test Fixture 1 for Template
Measurement per Section 40.6.1.1.3 of 802.3-2000 Standard

Note: The Ethernet package combines the functionality of the Test
Filter, Digital Oscilloscope, and Post Processing Block.

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Operation

Disturbing signal (Vd) characteristics (as specified in section 40.6.1.1.3 of the standard)

Characteristic Test Fixture 1 Test Fixture 2 Test Fixture 3

Waveform Sine Wave

Amplitude 2.8 V pk-pk 2.8 V pk-pk 5.4 V pk-pk

Frequency 31.25 MHz 31.25 MHz 20.833 MHz

Purity Harmonics should be at least -40 dB below fundamental

ETHERNET-OM-E Rev A ISSUED: November 2001 2–5

Figure 3. Example of Mask Testing Point A (Test
Mode 1)

Select a Point To Be Tested

When a point to be tested is selected

? The corresponding mask template is displayed.
? The signal is automatically triggered and aligned to the template.
? The signal is normalized to the template, as recommended by

? The signal can be averaged with continuos averaging.
? The operator can set averaging factor between 1:1 to 1:127 or

? Failure points are highlighted with red circles.
? The Pass/Fail testing result is displayed under the display grid.

The Mask Testing operation is similar to LeCroy PolyMask option.
(See also the PolyMask addendum for WavePro or Waverunner
oscilloscopes.)

Test errors are counted under the display grid, on line one, and
highlighted with red circles.

"Load More Masks" allows testing a specific peak against new or
modified masks (which can be created with the MaskMaker utility).
These templates can be loaded from a memory card, hard drive, or
floppy disk.

Suggested Application: the two default templates can be modified
and masks with different tolerances can be created.

Another possibility is to create mask templates, which will test only a
portion of the signal, allowing the user to focus only on that portion.

"Change Test Conditions" You may choose a specific action in
case the signal passes (or fails the test). As with other LeCroy

tolerance mask testing programs, a specific action may be taken if
the signal fails or passes the test. You may choose to stop the test,
store the results, dump the image to an external printer or drive, emit
a loud "beep," or output a 10 µs pulse at the CAL BNC.

Ethernet Package

the standard.

bypass averaging.

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Operation

"AUTO-FIT TO MASK" This soft key will align the signal to the
mask. It is recommended to do so before you start testing.

"Averaging" The default operation is testing
without averaging. However, averaging can be
turned on and set between 1:1 and 1:127. with the
knob.

"Testing" Turns the mask testing on and off.

Note: It is possible to fine tune the signal's position

relative to the mask template by adjusting the
horizontal and vertical positioning knobs.
(ANALYSIS CONTROL box)

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Ethernet Package

Peak Differential Output Voltage and Level Accuracy

Peak differential output voltage and level accuracy is measured
using the Test Fixture 1 setup (Figure 2). The signal is first filtered
(with a digital filter), then the disturbing signal is removed from the
composite waveform in the oscilloscope prior to post-processing.

Figure 4. The filtered test mode 1 waveform is
displayed on trace C. The measurement results for each
point are reported underneath, on the parameter line. If
required, the measurements can be averaged over several
sweeps by setting Parameter Averaging between 2 and 50.
The default averaging factor is 16.

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Operation

The following measurements are performed for the peak differential
output voltage and level accuracy test:

? DOVA – Amplitude of Peak A
? DOVB – Amplitude of Peak B. The standard limits the

amplitudes of Points A and B between 0.67 V and 0.82 V

? DOVC – Amplitude of Peak C
? DOVD – Amplitude of Peak D. The absolute value of Peaks C

and D shall differ by less than 2% from 0.5 times the average of
Peaks A and B.

? accAB – accuracy comparison between the absolute values of

Peaks A and B. The difference should be less than 1%

? accC – accuracy comparison between Peaks C and A
? accD – accuracy comparison between Peaks D and B

This soft key permits toggling between amplitude measurements of
peaks A, B, C, and D; and amplitude comparisons such as peak A
vs. peak B.

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Statistics: As with regular
parameter measurements
in LeCroy oscilloscopes,
statistics can be turned on
and off with the
corresponding soft key.

Parameter Averaging:

can be turned on and off;
16 is the default averaging
factor.

Maximum Output Droop

Ethernet Package

Figure 5. Test mode 1 waveform is also used for the
maximum output droop measurement; however, the test
fixture is changed to Test Fixture 2 (Figure 6).

As before, the grid displays the test mode 1 waveform. Points G and
J are evaluated. Under the display grid, the amplitude values of

these points are listed.

? drG – Voltage droop at point G relative to point F
? drJ – Voltage droop at point J relative to point H

(The maximum droop permitted by the IEEE 802.3 -2000 standard in
section 40.6.1.2.2 is 73.1%)

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Operation

ETHERNET PACKAGE

Figure 6. Transmitter Test Fixture 2 for Droop
Measurement per Section 40.6.1.1.3 of 802.3-2000 Standard

Test Fixture 2 is identical to test fixture 1, except for the test filter.
Now, the waveform remains unfiltered prior to processing.

Statistics and Parameter Averaging of the voltage droop
meaurement are identical to “Peak differential voltage and level
accuracy test.”

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Test Modes 2 and 3

Ethernet Package

These test modes are used for the measurement of transmitter
timing jitter.

Test mode 2 is used in combination with Test Fixture 4 (Figure 8) to
measure jitter in master mode (for more details, including the use of
"test channel," see section 40.6.1.1.1 of the standard)

Figure 7. Example of Transmitter Test Modes 2 and 3
Waveform

Section 40.6.1.2.5 of the 802.3-2000 standard describes the
transmitter timing jitter measurements. This section is divided into
two parts. The first part specifies the measurement of jitter in Master
Mode; the second part in Slave Mode.

In Master Mode, the transmitter works independently, clocked by the
master TX_TCLK.

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Operation

ETHERNET PACKAGE

Figure 8. Transmitter Test Fixture 4 for Transmitter
Jitter Measurement per Section 40.6.1.1.3 of 802.3-2000
Standard

The test Mode 2 waveform has to be generated and the
measurements performed with the Test Fixture 4 setup. Test Fixture
4 is used to measure jitter in both master and slave modes.

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Operation Mode

Jitter Measurements in Master and Slave Modes

Ethernet Package

Figure 9. Example of Jitter Measurement in Master
Mode. The upper grid displays an acquisition of the
differential data for 1 ms. The lower grid shows the
JitterTrack (or waveform) on TX_TCLK, filtered by the high­pass filter.

The measurement results are reported on lines 1-3, with statistics
turned on. See below for more details.

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Operation

Setup

Jitter in Master Mode

After setting up Test Fixture 4, connect the TX_TCLK signal to
Channel 1 of the oscilloscope.

The differential data signal can be probed in two ways. (Use the
"Select Input Source" button):

? with a differential probe (such as AP034 or equivalent)

connected to channel 2.
? with two single-ended probes connected to channels 2 and 3.
Note: The trigger is always on channel 2.

If probing is performed directly with two cables (on channels 2 and 3)
they should be coupled to 50 ? DC

When Test Mode 2 (Jitter in Master Mode) is selected, the following
menu is displayed: "Find Signal" will place the differential data
signal (Channel 2-3) on the upper grid. The acquisition length is
1ms. "Find Signal" sets the voltage range to the maximum to ensure
that the Jitter measurements will not be compromised by a low level
amplitude.

ETHERNET-OM-E Rev A ISSUED: November 2001 2–15

Statistics and Parameter Averaging are identical to the "Peak
differental voltage and level accuracy test."

"FIND JITTERTRACK" centers the JitterTrack (or jitter waveform)
on the lower grid signal if the trace is not displayed instantly. This is a

Jittertrack of the TX_TCLK signal, filtered by the high-pass filter, H

jf1 .

(For more details on JitterTrack, see the Jitter and Timing Analysis
Operator's Manual).

Ethernet Package

The following parameters are reported on lines 1 to 3 under the
lower grid:

Line 1 lists the accumulated jitter on TX_TCLK (tie@lv). The
standard specifies that the jitter level should be less than 1.4 ns.
That is the pk-pk accumulated jitter over the specified acquisition,
relative to an ideal clock.

Line 2 displays the measured jitter (hold) between TX_TCLK and the
corresponding zero crossing of the differential data (J

Line 3 shows the pk-pk jitter value of the measurement result on line
1, when the jitter waveform (track) is filtered by a high-pass filter with

the following transfer function:

j

)(

H

where f is specified in Hz. (section 40.6.1.1.2 of IEEE 802.3-2000)

Notes:

1. The standard requires summing the results on lines 2 and 3.

That means that the pk-pk jitter on the filtered JitterTrack should

be added to the J

than 0.3 ns

2. Over the 1 ms acquisition, a slow deviation (drift) in the

TX_TCLK signal may be noticed (Trace A). In such cases, it's

advisable to synchronize between the system's clock and the

DSO's 10 MHz reference input clock. In any case, the high-pass

filter will remove all low frequency components from the

JitterTrack. (Trace B).

f

1

jf

f

5000j

??f

value. The total amount should be less

txout

txout

).

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Operation

Jitter in Slave Mode

Test Fixture 4 (Figure 8) is used again, this time in conjunction with
the Test Mode 3 waveform. The difference (from the previous
measurement) is that now, the port is in configured in slave mode,
driven by TX_TCLK of the master port. The master port is connected
to the slave via the test channel defined in section 40.6.1.1.1.

The measurement result displayed on line 1, is the jitter between the
master and slave TX_TCLK signals (hold). The standard limits it to
less than 1.4 ns.

Line 2 shows the pk-pk jitter value on the Slave TX_TCLK, with
TX_TCLK jitter waveform (track), filtered by the high-pass filter with
the following transfer function (as specified in section 40.6.1.2.5 of
IEEE 802.3-2000):

j

)(

f

2

H jf

Line 3 displays the measured jitter between the slave TX_TCLK and
the corresponding zero crossing of the differential data (J
measurement is similar to the measurement performed in master
mode (hold).

Line 4 shows the pk-pk jitter value on filtered Master TX_TCLK,
which is essential for the jitter calculation on line 2.

Note: The standard requires summing the results on lines 2 and 3.
That means that the pk-pk jitter of the filtered JitterTrack should be

added to J

0.4 ns greater than the pk-pk jitter on line 4.

value. The total amount should be no more than

txout

f

32000j

??f

). This

txout

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Transmitter Distortion Measurement

Select Test Mode 4 from the menu:

Ethernet Package

Figure 10. As can be seen in this example, the input
signal is displayed on the grid. Below the grid, the result of
the peak distortion measurement is reported on the
parameter line. Averaging and statistics are identical to Test
Mode 1 measurements.

Note: The peak distortion measurement is calculated by following
the MATLAB code example from section 40.6.1.2.4

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Operation

The peak distortion measurement is performed using Test Fixture 3
(Figure 11). As before, filtering, data acquisition, and removal of the
disturbing signal from the composite waveform are performed in the
oscilloscope.

ETHERNET PACKAGE

ETHERNET-OM-E Rev A ISSUED: November 2001 2–19

Figure 11. Transmitter Test Fixture 3 for Distortion
Measurement per Section 40.6.1.1.3 of 802.3-2000 Standard

The peak distortion is determined by sampling the differential data
(A) with TX_TCLK and processing 2047 consecutive samples. The
differential data signal has to be filtered (B) prior to processing, with
the following filter:

j

)(??

f

H

tf

where f is specified in Hz.

Note: The standard limits the distortion to less than 10 mV peak.(see
section 40.6.1.2.4)

f

6

f

10*2j

100Base-TX

Ethernet Package

The 100Base-TX standard uses the MLT-3 signaling code:

See section 9.1.8 of ANSI X3.263-1995 standard.
The LeCroy Ethernet Package provides three test types for this

standard:

? Mask testing
? Signal measurements
? Jitter measurement

After the 100Base-TX is selected from the start menu, the menu at
left is displayed.

Select Test: Selects between Outputs (signal measurements),
Templates (mask testing) and Jitter measurements.

Note: An idle transmission between two 100Base-TX stations can
be used for probing 100Base-TX signals, after the auto negotiation
process is over and a stable 100Base-TX link is established. Notice
that some measurements are performed on 96 ns wide pulses,
some on 80 ns pulses, and some on 16 ns pulses. For signal
parameter measurements, the DSO is triggered to capture data
following a 96 ns positive pulse.

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Operation

PIN NO. FUNCTION

1 TX_D1+
2 TX_D1­3 RX_D2+
4 BI_D3+
5 BI_D3­6 RX_D2­7 BI_D4+
8 BI_D4-

Figure 12. Example of probing 100Base-TX signals with
an AP034 differential probe

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Mask Testing

Ethernet Package

Figure 13. An example of 100Base-TX mask testing.
When this test is selected, the mask template is displayed,
with the signal triggered and automatically aligned with the
template. Red circles indicate the points of failure. The
Pass/Fail test results are shown below the grid, on the
parameter line.

The Mask Testing feature is similar to the LeCroy PolyMask option.

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Operation

"Load More Masks" allows testing against new or modified masks
created with the MaskMaker utility. Mask templates can be loaded
from a memory card, hard drive, or floppy disk.

Suggested applications: The default template can be modified,
and new masks with different tolerances can be created.

Another possibility is to create mask templates that will test only a
portion of the signal, allowing you to focus on a specific point only.

"Change Test Conditions" As with other LeCroy tolerance mask
testing programs, a specific action can be taken if the signal fails or

passes the test. You can choose to stop the test, store the results,
dump the image to an external printer or drive, emit a loud "beep," or
output a 10 µs pulse at the CAL BNC.

"AUTO-FIT TO MASK" This soft key will align the signal with the
mask. It is recommended to do so before the start of testing.

Notes:

1. It is possible to fine tune the signal's position relative to the mask

template by adjusting the horizontal, vertical and zoom

positioning knobs (ANALYSIS CONTROL box).

2. If an eye pattern is desired, press the ANALOG PERSISTENCE

button.

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"Testing" Turns the mask testing on or off.

Signal Measurements

Ethernet Package

Figure 14. Example of 100Base-TX Signal
Measurements

Trace A is a 100 µs acquisition of the MLT-3 input signal. Below the
grid, five measurement results are reported:

? feDOV – Differential Output Voltage: 1.9 V - 2.1 V. This is the

total signal (positive plus negative) pk-pk value

? feSAS – Signal Amplitude Symmetry:

?

Vout

?

?

Vout

? ferf – Rise/Fall times: 3 ns -5 ns
? ferfs – Rise/Fall symmetry : ? 0.5 ns
? feDCD – Duty Cycle Distortion +/-0.25 ns

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02.198.0 ?

Operation

? feovr – Signal Overshoot maximum allowed is 5% above steady

state voltage
The feDOV and feSAS measurements are closely related. Only one

of them is displayed at a time. You can select between showing
feDOV or feSAS with a soft key. (See Figure 14.)

Notes:

1. The feDOV, feSAS, and feover measurements are performed

on a 96 ns positive reference pulse. The DSO acquisition will be

triggered by this pulse (Channel 2).

2. ferf and ferfs measurements are performed on an 80 ns positive

reference pulse.

3. feDCD measurement is performed on 16 ns wide pulses.

ETHERNET-OM-E Rev A ISSUED: November 2001 2–25

Statistics: As with regular parameter measurements in
LeCroy oscilloscopes, statistics can be turned on and
off with the corresponding soft key.

Parameter Averaging: A global averaging factor for all
measurements can be set with another soft key. The
default averaging factor is 16, but it can be set from 2 to

50.

Jitter Measurement

Ethernet Package

Figure 15. The upper grid displays the MLT-3 signal.
The JitterTrack of the signal is displayed on the lower grid.
The peak-to-peak jitter value is reported below the grid

The jitter pk-pk measurement is a tie@lv measurement, i.e., the total
jitter over 100 µs, relative to an ideal clock. The ideal clock is
calculated from the data stream. (See the Jitter and Timing Analysis
Operator's Manual).

"Find Signal " will place the differential data signal (Channel 2-3) on
the upper grid. The acquisition length is 100 µs. "Find Signal" sets
the voltage range to the maximum to ensure that the Jitter
measurements will not be compromised by a low-level amplitude.

Averaging and Statistics are similar to Signal Measurements.
"FIND JITTERTRACK" centers the JitterTrack (or jitter waveform) on

the lower grid signal if the trace is not displayed instantly. (For more

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Operation

details on JitterTrack, see the Jitter and Timing Analysis Operator's
Manual).

Over the 100 µs acquisition, a slow deviation (drift) in the TX_TCLK
signal may sometimes be noticed (Trace A). In such cases, it's
advisable to synchronize between the system's clock and the DSO's
10 MHz reference input clock. In any case, a high-pass filter will
remove all low frequency components from the JitterTrack.

# # #

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BLANK PAGE

Ethernet Package

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3

Remote Commands

FUNCTION DEFINE, DEF

DESCRIPTION In addition to the parameters listed in your scope’s Remote

Control Manual, there is another parameter for the DEF EQN
command for the Ethernet package: ETHERNET (Tx).

COMMAND SYNTAX Tx:DEF EQN, “ETHERNET <source>”,PROC,<value>

Tx =: {T1,T2,T3,T4}
<source> =: {TA,TB,TC,TD,M1,M2,M3,M4,C1,C2,C3,C4}
processing <value> =:
NOOP no operation
REM_3125 remove 31.25 MHz disturbing signal
HPF apply test high-pass filter
MJHPF apply master mode jitter signal HP F),
SJHPF apply slave mode jitter signal HPF
GBMSK premask processing for gigabit mask testing,

remove 31.25 MHz disturbing signal, apply test
high-pass filter, position signal to a stable point,
perform 1-bit ERES on the signal

FENET do basic Fast Ethernet calculations and perform

1-bit ERES for mask testing)

ETHERNET-OM-E Rev A ISSUED: November 2001 3–1

Ethernet Package

FUNCTION ENET_AVG, ENAV

DESCRIPTION In the Ethernet package, this command controls how many

measurements are averaged before being returned as a single
result of a parameter. This helps the value appear stable and
readable on the parameter display. If statistics are enabled, it
reduces sigma and the range between low and high results.
(Outside of the Ethernet package, parameters do not average
internally. They return each measurement as a result; statistics,
therefore, are for individual measurements.) If this internal
averaging is enabled, the parameter display will show "- - -" until
the required number of measurements has been made so that one
result can be returned. After that the display will change each
time the required number of measurements has been made to
produce a new result.

COMMAND SYNTAX ENAV {ON,OFF}

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Remote Commands

FUNCTION ENET_AVG_COUNT, ENCT

DESCRIPTION In the Ethernet package, this command controls how many

measurements are averaged before being returned as a single
result of a parameter. This helps the value appear stable and
readable on the parameter display. If statistics are enabled, it
reduces sigma and the range between low and high results.
(Outside of the Ethernet package, parameters do not average
internally. They return each measurement as a result; statistics,
therefore, are for individual measurements.) If this internal
averaging is enabled, the parameter display will show "- - -" until
the required number of measurements has been made so that one
result can be returned. After that the display will change each
time the required number of measurements has been made to
produce a new result.

COMMAND SYNTAX ENCT <value>

<value> =: 2 through 50; the default is 16

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Ethernet Package

FUNCTION PARAMETER_CUSTOM, PACU

DESCRIPTION The PARAMETER_CUSTOM command controls the parameters

that have customizable qualifiers, and can also be used to assign
any parameter for histograms. The parameters for the Ethernet
option take only a trace or channel for input.

COMMAND SYNTAX <source>:PACU,<value>

<source> =: {TA,TB,TC,TD,M1,M2,M3,M4,C1,C2,C3,C4}
<value> =:
DOVA gigabit Ethernet voltage at point A
DOVB gigabit Ethernet voltage at point B
DOVC gigabit Ethernet voltage at point C
DOVD gigabit Ethernet voltage at point D
ACCAB gigabit Ethernet voltage accuracy between points

A and B
ACCC gigabit Ethernet voltage accuracy at point C
ACCD gigabit Ethernet voltage accuracy at point D
DRG gigabit Ethernet droop at point G relative to point

F
DRJ gigabit Ethernet droop at point J relative to point H
DIST gigabit Ethernet distortion calculation
FEDOV fast Ethernet differential output voltage
FEDSAS fast Ethernet signal amplitude symmetry
FEOVR fast Ethernet overshoot
FERF fast Ethernet rise/fall time
FERFS fast Ethernet rise/fall time symmetry
FEDCD fast Ethernet duty cycle distortion
JPKPK peak-to-peak jitter measurement

# # #

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4

Specifications

The Ethernet Package evaluates the following:

1000Base-T

Test Where / What The standard specifies

Specifications

Peak Differential Output
Voltage and Level
Accuracy

Mask Test Peaks A, B, C, D, F and H 2 template boundaries
Maximum Voltage Droop DRG, DRJ, Voltage droop at peaks G

Jitter in Master Mode

Jitter in Slave Mode

Transmitter Distortion At least 2047 samples Tds < 10 mV

DOVA, DOVB, Amplitude measurement
of peaks A, B
DOVC, DOVD Amplitude measurement
of peaks C, D
ACCAB Amplitude comparison: peak A
vs. B
ACCC Amplitude comparison: peak C
vs. A
ACCD Amplitude comparison: peak B
vs. D

and J
tie@lv on TX_TCLK

hold, J

txout

jpkpk, the Pk-Pk Jitter on TX_TCLK
(filtered)
hold, Slave TX_TCLK relative to Master
TX_TCLK
jpkpk jitter value on the Slave TX_TCLK
(filtered)
hold, between Slave TX_TCLK and
corresponding diff data zero crossing
jpk-pk jitter value on Master TX_TCLK
(filtered)

Between 0.67 V and 0.82 V

1/2 of absolute averaged A, B

amplitude values

< 1%

< 2%

< 2%

G > 0.731F; J > 0.731H

See section 40.6.1.2.5 in
clause 40 of 802.3-2000
standard.

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Ethernet Package

100Base-TX

Test Where / What The standard specifies

Mask Test One mask template Eye diagram template boundaries
Jitter Measurement tie@lv on the MLT-3 signal < 1.4 ns
Signal Measurements

feDOV 0.95 V ? DOV ? 1.05 V
feSAS 0.98 – 1.02
ferf Rise/Fall Times 3 ns ? Vrs ? 5 ns
ferfs Rise/Fall Symmetry ? 0.5 ns
feDCD +/-0.25 ns
feovr Overshoot +5% steady state voltage

# # #

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