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Tuning the Analyzer for a Specific DUT
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Keysight U4301 PCIe Gen3 Analyzer User’s Guide
PCIe Gen3 Tuning Overview
What is Tuning
Tuning
is the process of adjusting Keysight’s probing system to remove the effects of different driving
silicon, termination silicon (or other termination schemes), imperfect transmission paths, and the fact
that the probes may not be in the "ideal" location for receiving a high-speed signal (that is, at the end
of the transmission path).
Furthermore, a PCIe Gen3 system will negotiate its own TX Linear Equalization, and you would like to
have the largest eye possible. Tuning does not affect either the transmitter or the receiver; it is used
only to increase the eye as seen by the U4301 Analyzer module. This process involves getting the
system/device-under-test to a stable PCIe Gen3 transmission state which the analyzer then
optimizes its own equalizations settings for.
How Tuning Works
For tuning, you:
• either use a predefined physical layer tuning (.ptu) file with default tuning values appropriate for
your probing and connection setup.
• or create a physical layer tuning (.ptu) file..
The .ptu file contains the information necessary to adjust the probing system for a specific
device-under-test (DUT). At the 8 Gbps speed, you then need to load this .ptu file into the U4301
Analyzer module’s software to have the best possible eye at the Analyzer.
It is recommended that you first use a predefined .ptu file with default tuning values. If the default
tuning values do not provide robust and clean tracing results, you should consider creating your own
.ptu file.
You can create or fine tune a .ptu file using the Keysight Logic and Protocol Analyzer GUI.
When to Perform Tuning
You should only perform tuning when all of the following conditions are met:
• Poor trace quality which may include red packets, triggers on “Loss of Sync” or “Channel
Bonding”.
• No Recovery cycles (that is, cannot Trigger on “Any TS”) on the target.
• When no existing .ptu files are able to provide robust tracing.
Default and User Defined .ptu Files
A set of default tuning (.ptu) files are provided with the Keysight Logic and Protocol Analyzer
software. These tuning files contain the probe defaults to compensate for the signal impairments
associated with the probe. These files are named on the basis of the probe type for which these are
created. Based on the probe type you are using, one of these files is used and if the trace quality is
clean, you do not need to tune further by creating your own .ptu file. These default .ptu files work fine
and support robust tracing in situations where the targets have margin. The following screen displays
the location of these default ptu files.
Summary of Contents for U4301
Page 1: ...Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 10: ...10 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 15: ...Keysight U4301 PCIe Gen3 Analyzer User s Guide 15 Contents 12 Glossary Index ...
Page 16: ...16 Keysight U4301 PCIe Gen3 Analyzer User s Guide Contents ...
Page 18: ...1 Hardware and Software Installation 18 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 20: ...2 Probing Options for PCIe Gen3 20 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 32: ...3 Specifying the Connection Setup 32 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 54: ...5 Tuning the Analyzer for a Specific DUT 54 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 72: ...7 Running Stopping Captures 72 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 78: ...8 Viewing PCIe Gen3 Packets 78 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 79: ...Keysight U4301 PCIe Gen3 Analyzer User s Guide 79 Viewing PCIe Gen3 Packets 8 ...
Page 96: ...8 Viewing PCIe Gen3 Packets 96 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 200: ...12 Glossary 200 Keysight U4301 PCIe Gen3 Analyzer User s Guide ...
Page 203: ...Keysight U4301 PCIe Gen3 Analyzer User s Guide 203 ...