EYE DOCTOR™

As the symbol rates of systems

have increased, the measurement

challenges have also and with the

adoption of receiver equalization,

traditional jitter and noise measure-

ments are becoming inadequate

for determining interoperability.

Eye Doctor™ is a DSO-based

instrumentation and simulation

system which addresses these

measurement challenges and is

a dramatic leap in interoperability

and compliance testing capability.

Eye Doctor provides the tools to

undo or compensate many common

forms of distortion thereby increas-

ing signal to noise, opening eyes,

increasing rise time, reducing jitter

restoring lost bandwidth and improv-

ing waveform fidelity.

Measuring Equalized

Systems

Imperfections such as through

holes, connectors, vias and package

pins cause distortions in the high

frequency content of high bit rate

signals. The resulting eye is often

closed or nearly closed. The tradi-

tional approach to interoperability

testing involves measuring the

channel response and the transmit-

ter signal quality against compliance

masks designed so that the signal

eye and jitter will enable error-free

operation. In an equalized system,

the channel, transmitter and receiver

are closely coupled and interoper-

ability is determined by whether the

signal can be equalized. What is

needed is a method to quantitatively

measure the interoperability of

these systems.

Leading Features

• Full signal integrity analysis

of equalized receiver signal

• Real time co-simulation

of measured signals and

measured or modeled network

characteristics

• Performance margin analysis

in equalized systems

• De-embedding of fixture and

probe responses

• High accuracy far-end channel

measurements

• Emulates any combination of

DFE and FFE equalizers

• Automatic equalizer coefficient

optimization

• Direct entry of FFE and DFE

coefficients

Virtual Probing™ and equalizer emulation enhance the capability of the SDA to allowthe measurement of serial data signals in equalized systems

Tools for Next Generation Serial Data Analysis

Eye Doctor

Eye doctor consists of two

elements; Virtual Probing™ and

equalized receiver emulation.

Virtual Probing enhances the

accuracy of measurements

made on distorted waveforms

while equalized receiver emulation

allows measurements to be made

from a “receivers eye view.”

The ideal view of the signal within

the receiver allows accurate total

jitter and bit error rate measurements

that are representative of actual

system performance.

Virtual Probing

Probes and fixtures are not perfect

and their presence in the circuit

impacts both the loading on the

DUT as well as the waveform seen

by the oscilloscope. Virtual Probing

is a powerful signal processing tool

which enables the user to measure

a signal anywhere within a system

and then project a response at any

other desired point. This feature

works by using S-parameter files

of the various components in the

system to derive a filter which

relates the desired measured signal

to the acquired waveform. For

example, measurements can be

made where the cleanest signal is

available, usually at the transmitter,

and the corrupted signal at the

far-end of the channel (at the end

of the backplane) can be simulated

thus eliminating probe and instru-

ment noise from the measurement.

The derived filter takes into account

all of the interactions among the

elements of the system and trans-

mitter signal including differential

to common mode conversion, near-

end and far-end crosstalk.

Virtual Probing can be used to

de-embed probe and fixture responses

from measurements thereby improv-

ing the accuracy of signal integrity

measurements.

2

Current generation serial data systems ensure interoperability using compliance measurements. Next generation systems employingequalization require new methods for determining interoperability. With the signal eye closed, traditional compliance measurements are no longer sufficient.

Equalizer Emulation

Eye Doctor features equalized receiver

emulation which includes both Feed

Forward Equalization (FFE) and Decision

Feedback Equalization (DFE) along with

clock recovery and a variable decision

threshold. This ideal receiver reveals

the signal as seen within a real receiver

at the detector where it is impossible

to probe. The equalized signal can be

measured using the powerful jitter and

signal analysis software in the SDA

allowing the bit error rate, total jitter,

and eye opening to be measured thus

giving a precise indication of the

performance margin. Because the

receiver emulation is ideal, the margins

are measured independently of meas-

urement system and receiver noise.

3

Virtual Probing simulates signals from any point within the system using a singlemeasured waveform. The virtual probe shown here is co-simulating a backplanewhich closes the eye. The equalizer corrects the distortion caused by the back-plane which opens the eye. The Processing Web Editor is used to connect theequalizer and Virtual Probing elements in an intuitive signal flow diagram layout.

Equalizer emulation simulates the signal as viewed within the receiver. The component can automatically determine the optimum weighting coefficients for both FFE and DFE with the number of taps for eachselected by the user. Coefficients can also be entered directly. The full jitter analysis capability of the SDA is available on the equalized signal.

Equalizer Emulation

• Up to 20 tap linear tapped delay line equalizer (transversal filter).

• PLL for clock recovery with variable loop bandwidth.

• Up to 20 tap Decision Feedback Equalizer (DFE) including erasure DFE.

• Clock skew adjustment.

• Outputs for equalized waveform (slicer input), data waveform (slicer output), and recovered clock.

• Error waveform output for user defined equalizer optimizations.

• Automatic blind adaptation using built-in LMS algorithms.

• Multi-level detection threshold supports duobinary and multilevel signaling systems.

Virtual Probing

• Provides waveforms that compensate for probe loadingeffects within bandwidth limitations of the system.

• Produces linear filters that operate on up to 8 inputs and provides up to 8 outputs.

• Simple text file system description similar to Spice.

• Accepts Touchstone format S-parameter file networkdevice descriptions.

• Includes simple device descriptions such as ideal tees,power splitter, open, short, thru plus lumped elementssuch as resistors, capacitors and inductors.

Eye Doctor is optional on the following SDA and

WaveExpert models

• Serial Data Analyzers SDA 6000A, SDA 6020, SDA 9000, SDA 11000, SDA 18000

• SDA 100G, NRO 9000 and WaveExpert 100H

Product Description Product Code

Eye Doctor (Virtual probe and EYEDRequalizer emulation bundle)Virtual Probe EYEDR-VPEqualizer Emulation EYEDR-EQ

Retrofit Kit for Eye Doctor (Virtual probe and RK-EYEDRequalizer emulation bundle)Retrofit Kit for Virtual Probe RK-EYEDR-VPRetrofit Kit for Equalizer Emulation RK-EYEDR-EQ

Customer ServiceLeCroy oscilloscopes are designed, built, and tested to ensure high reliability. In the unlikely event you experience difficulties, the WaveExpert Series oscilloscopes and modules are warrantedfor a period of one year, and our probes are warranted for one year.

The SDA Series Serial Data Analyzers are fully warranted forthree years.

This warranty includes:

• No charge for return shipping • Long-term 7-year support• Upgrade to latest software at no charge

Ordering Information

EyeDrDS_W2_10July07

Local sales offices are located throughout the world.

To find the most convenient one visit www.lecroy.com

1-800-5-LeCroy www.lecroy.com

© 2007 by LeCroy Corporation. All rights reserved. Specifications, prices, availability, and delivery subject to changewithout notice. Product or brand names are trademarks or requested trademarks of their respective holders.

Specifications