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Developing Customized Measurements and

Automated Analysis Routines using MATLAB®

Guillaume Millot

MathWorks France

2

MathWorks Overview

Founded in 1984 in the US

Several software platforms : MATLAB

Headquarters in Boston

Offices throughout Europe including France, Germany, and the United Kingdom

Used by more than 1,000,000 users in over 175 countries

Used in over 3,500 universities

3

Technical computing language

Development environment

More than 1500 functions Math

2D, 3D graphics and GUI design

File I/O

Calling C/C++, Fortran, Java, COM

Toolboxes for signal and image

processing, connection to hardware

or databases, statistics, optimization, …

Available from MathWorks or Agilent with

Infiniium and InfiniiVision oscilloscopes

and other instruments

MATLAB The leading environment for technical computing

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Technical Computing Workflow

Reporting and

Documentation

Outputs for Design

Deployment

Share

Explore & Discover

Data Analysis

& Modeling

Files

Software

Hardware

Access

Code & Applications

Automate

Algorithm

Development

Application

Development

5

Measurement, analysis, and testing challenges

for high speed serial and other systems

1. Creating analysis and measurement routines for

designing and testing your system

2. Interfacing and verifying these routines with live

measured data

3. Visualizing analysis routines to improve signal

integrity

6

Measurement, analysis, and testing challenges

for high speed serial and other systems

1. Creating analysis and measurement routines

for designing and testing your system

2. Interfacing and verifying these routines with live

measured data

3. Visualizing analysis routines to improve signal

integrity

7 7

Example: Developing an analysis routine to

perform device characterization

CRj

jT

1

1

In

Out

Goals: 1. Characterize the unknown device (it will be a low-pass filter)

2. Analyze the device (in this case the low-pass filter) to determine if

it behaves as designed

CRFo

2

1

Transfer Function:

Cutoff Frequency:

0 2000 4000 6000 8000 10000 12000-1

0

1

0 2000 4000 6000 8000 10000 12000-1

0

1

0 2000 4000 6000 8000 10000 12000-1

0

1

0 2000 4000 6000 8000 10000 12000-1

0

1 ? V+

V-

V+

V-

R

C In Out

8

Agilent

Signal Generator

8

CR

CRjjT

o

1

1

1

V+

V-

V+

V-

R = 1kW

C = .1mF

Syste

m I

nput

Response

GPIB, LAN, or USB

Agilent

Oscilloscope

Device Characterization Interactively develop your transfer function and analysis

routines

MATLAB

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Device Characterization Ideal end result

Circuit to be

characterized

Automated Circuit Tool application

developed in MATLAB to characterize

the circuit and determine if it behaves

as designed

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Demo Clip

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Device Characterization Develop and Deploy Application

Create custom graphical user interface to

encapsulate/automate your MATLAB analysis

routine for others to use

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Measurement, analysis, and testing challenges

for high speed serial and other systems

1. Creating analysis and measurement routines for

designing and testing your system

2. Interfacing and verifying these routines with

live measured data

3. Visualizing analysis routines to improve

signal integrity

13

MATLAB Connects to Your Hardware Devices

Data Acquisition Toolbox

Plug-in data acquisition devices

and sound cards

Instrument Control Toolbox

Instruments and RS-232

serial devices

MATLAB

Interfaces for communicating

with everything

Image Acquisition Toolbox

Image capture devices

Vehicle Network Toolbox

CAN bus devices using CAN

and XCP protocols

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Creating a pre-distortion filter and verifying

it with live Agilent oscilloscope signals

Task

– Improve system BER

Solution

– Characterize system’s

response

– Use the characterization

to develop pre-distortion

filter

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Step 1:

Waveform acquisition from Agilent Oscilloscope

Use Test & Measurement Tool on or off the scope

Test & Measurement Tool provided with MATLAB’s Instrument Control Toolbox

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Step 2:

Use acquired signals to design pre-distortion filter

Use system identification functions to design FIR pre-distortion filter

-8 -7.95 -7.9 -7.85 -7.8 -7.75 -7.7 -7.65 -7.6 -7.55 -7.5

x 10-7

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

Time

Voltage

With thumb

-8 -7.95 -7.9 -7.85 -7.8 -7.75 -7.7 -7.65 -7.6 -7.55 -7.5

x 10-7

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

Time

Voltage

Sans thumb

In-phase Signal

Time (s)A

mplit

ude (

AU

)0 1 2 3 4 5 6 7

x 10-10

-1

-0.5

0

0.5

1

In-phase Signal

Time (s)

Am

plit

ude (

AU

)

0 1 2 3 4 5 6 7

x 10-10

-1

-0.5

0

0.5

1

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Step 3: Execute your analysis routines directly on

an Agilent oscilloscope

• Agilent and MathWorks teamed up to create a

custom development environment using

Infiniium oscilloscopes and MATLAB to

address unique and special measurement

needs.

• Requires no knowledge of MATLAB

to operate on the scope

• Agilent automatically includes the MATLAB

software environment as part of the N8806A

UDF option.

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Measurement, analysis, and testing challenges

for high speed serial and other systems

1. Creating analysis and measurement routines for

designing and testing your system

2. Interfacing and verifying these routines with live

measured data

3. Visualizing analysis routines to improve

signal integrity

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Visualizing MATLAB analysis routines

to improve signal integrity

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High-speed digital signals are

susceptible to signal integrity issues due

to limitations of the physical interface.

You need: 1. Analysis routines to analyse backplane

behaviour.

2. Acquire live signals from Agilent

instruments to create and verify these

analysis routines.

3. Applications to automate the execution of

these measurement and analysis

routines.

MATLAB provides the capabilities to create analysis routines, interface

to Agilent instruments to acquire live signals to verify them, and

language and tools to automate the execution.

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MATLAB Code for Acquiring Live Signals from

Agilent instruments

%% Directly acquire digital signals from Agilent oscilloscope or

S-Parameters from Agilent network analyzer ... %% Convert the 16-Port to 4-Port S-Parameters SingleEnded4PortSParams = … snp2smp(SingleEnded16PortData.S_Parameters, … SingleEnded16PortData.Z0, [3 14 4 13]); %% Convert 4-Port to 2-Port Differential S-Parameters Differential2PortSparamsForChannel = … s2sdd(SingleEnded4PortSParams); %% Calculate the Frequency Response DifferentialFreqResponseForChannel = … s2tf(Differential2PortSparamsForChannel); %% Fit Differential Frequency Response to Rational Function ModelforForwardChannel = … rationalfit(Freq, DifferentialFreqResponseForChannel); ...

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MATLAB Code for Visualizing Jitter of

Acquired Signals

%% First Input and its Output due to CrossTalk InputSignal_1 = GenerateInputsignal(TotalSampleNumber, …); OutputSignal_1 = timeresp(ModelforCrosstalk_1, InputSignal_1, …); %% Second Input and its Output (forward channel) InputSignal_2 = GenerateInputsignal(TotalSampleNumber, …); OutputSignal_2 = timeresp(ModelforForwardChannel,InputSignal_2, …); ... %% The Output Signal of the Second Channel OutputSignal = OutputSignal_1 + OutputSignal_2 + OutputSignal_3 … + OutputSignal_4; %% Eye Diagram of the Output Signal EyeDiagram = commscope.eyediagram('SamplingFrequency', … 1./SampleTime, 'SamplesPerSymbol', OverSamplingFactor) update(EyeDiagram, OutputSignal); %% Jitter Measurements analyze(EyeDiagram); Measurements = EyeDiagram.Measurements

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Visualizing of Eye Diagram Characteristics

in MATLAB

Total jitter: deterministic jitter and random jitter

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Visualizing of Eye Diagram Characteristics

in MATLAB (continued)

Deterministic jitter only, no random jitter

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Measurement, Analysis, and Testing Challenges

Creating analysis and measurement routines for designing and testing your system

MATLAB is a software environment and a programming language made for design and test engineers to be productive

Supports analysis routine creation, data visualization, and application development

Interfacing and verifying these routines with live measured data Integrated measurement and analysis provided with MATLAB

Ability to execute your MATLAB analysis routines directly on Agilent oscilloscopes using N8806A UDF

Visualizing analysis routines to improve signal integrity Analysis routines created in MATLAB can be utilized to visualize

and understand eye diagram characteristics to help improve signal integrity of your high-speed systems

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Agilent and MATLAB Resources for Developing

Customized Measurement and Analysis Routines

MATLAB overview: www.mathworks.com/matlab

Instrument Control Toolbox overview:

www.mathworks.com/products/instrument

Signal Processing Toolbox overview: www.mathworks.com/products/signal

Agilent resource page on MATLAB for Agilent Infiniium and InfiniiVision

scopes: www.agilent.com/find/matlab_oscilloscopes

Agilent resource page on MATLAB with Agilent instruments:

www.agilent.com/find/matlab

Agilent N8806A User Defined Function: www.agilent.com/find/udf

Using MATLAB to control Agilent oscilloscopes, function generators, and

other instruments www.mathworks.com/agilent

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EXTRA SLIDES

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Device Characterization Step 1: Stimulate device and acquire device responses

Configure Agilent signal generator and Agilent

oscilloscope with Instrument Control Toolbox

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Device Characterization Step 2: Visualize Data

Plot data Select data to plot in the Workspace Browser

Select desired plot type from the Plot button

The equivalent command is displayed in the Command

Window

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Device Characterization Step 3: Pre-process Data

Scale the data Interactively zoom to explore data – identify scaling problem

Correct scaling with simple MATLAB command

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Device Characterization Step 4: Visualize Original and Processed Data

Build custom visualization with Plot Tools Enable Plot Tools (plottools) with button on Figure

Toolbar

Drag and drop to layout axes and add data to plots

Customize and annotate plots

Automatically generate MATLAB code to reproduce

visualization with new data

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Device Characterization Step 5: Estimate Transfer Function

Estimate Transfer Function with the Signal

Processing Toolbox Search the Help for desired functionality

Run sample code directly from the Help Browser

Modify commands for our data

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Device Characterization Step 6: Compare with Expected Results

Compute expected response with governing equations

Fit theoretical response to measured response with the

Curve Fitting Toolbox Use Curve Fitting Tool to interactively design and analyze a fit to

our data

Automatically generate MATLAB code to compute fit with new data

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Device Characterization Step 7: Automate Repetition of Analysis

Write custom script to automate workflow Create MATLAB file from selected commands in Command

History

Add comments to generated code in Editor

Use %% to divide code into individual cells to improve

readability and support cell execution

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Device Characterization Step 8: Publish Results

Publish MATLAB file directly to HTML document Click “Publish to HTML” button in Editor Toolbar

Each cell is converted to a section of the document

All code, comments, and output are captured in the document

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Instrument Control Toolbox Enables MATLAB to configure, control, and transfer data with instruments

such as oscilloscopes, pulse generators, and signal analyzers

Integrate instruments into

MATLAB applications and

Simulink

Interactive tool for detecting and

controlling instruments

Automatic code generation for

faster and easier implementation

Support for IVI, VXIplug&play,

and MATLAB instrument drivers

Support for common

communication protocols

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Instrument Control Toolbox and

N8806A User Defined Function

Instrument Control Toolbox

Use MATLAB to control the oscilloscope, either on or off the scope, to automate measurements

Download data directly into MATLAB for analysis and to build complete GUI-based test applications.

User Defined Function

Use MATLAB directly on Infiniium oscilloscopes to make customized measurements.

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N8806A User Defined Function

How to Access

In “Analyze” pull down

menu, click “Math…”

Then select your new

function from the “Operator”

pull down list

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