User guide

• Frame Error Ratio (FER)
• Calculated Bit Error Ratio (cBER)
• Filler Symbol Ratio (FSR)
• Disparity Error Ratio (DER)
• Illegal Symbol Ratio (ISR)
In order to stress your device under test, you can then, for example, add errors to
the data stream or switch between different patterns and view the resulting
"BER" / "8B/10B Comparison" / "Bit Comparison without PCIe3 SKPOS" / "Bit
Comparison without USB3.1 SKPOS". Or you can adjust the output port parameters
or the error detector's sampling point while the measurement is running and watch
the resulting "BER" / "8B/10B Comparison" / "Bit Comparison without PCIe3
SKPOS" / "Bit Comparison without USB3.1 SKPOS" immediately.
Such measurements can be used to find out the benchmark data, for example, for
a device prototype.
Test Methods
You can analyze the behavior of your device by employing several test methods. If
the changes in the test setup affect the "BER" / "8B/10B Comparison" / "Bit
Comparison without PCIe3 SKPOS" / "Bit Comparison without USB3.1 SKPOS",
you can immediately notice it on the screen. The resulting changes in the "BER" /
"8B/10B Comparison" / "Bit Comparison without PCIe3 SKPOS" / "Bit
Comparison without USB3.1 SKPOS" let you learn about the DUT's behavior and
limitations. Some examples of modifications that you can make are listed below.
• Add errors to the data stream. See “Error Addition/Insertion - Concepts ” on
page 157 for details. You can, for example, perform a confidence test of your
measurement setup. The analyzer should recognize all errors that you add. If
it does not, you may have a problem with your measurement setup. See “Setup
Problems - Concepts” on page 469 for details.
• Use alternating patterns to switch between different data streams. For example,
if your device is designed to turn off in response to a high "BER" / "8B/10B
Comparison" / "Bit Comparison without PCIe3 SKPOS / "Bit Comparison
without USB3.1 SKPOS"", you can check if your device behaves as expected.
And you can observe what the "BER" / "8B/10B Comparison" / "Bit
Comparison without PCIe3 SKPOS" is prior to data loss. See “Pattern
Alternation - Concepts ” on page 161 for details.
• Manipulate the signal being generated by the pattern generator, as described
in “Setting up the Pattern Generator - Concepts ” on page 121.
• Adjust the sampling point to see the effect on the "BER" / "8B/10B
Comparison" / "Bit Comparison without PCIe3 SKPOS" / "Bit Comparison
without USB3.1 SKPOS". See “Sampling Point Setup - Concepts ” on page
193 for details.
• Make modifications to your device setup.
7 Evaluating Results
362 Agilent J-BERT N4903B High-Performance Serial BERT