Protocol analysis
R&S
®
RTP
916User Manual 1337.9952.02 ─ 12
There are two ways to generate eye diagrams on the R&S RTP:
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Standard eye diagrams, which are a superposition of repetitively sampled digital
data.
●
DDR eye diagrams, which are generated by superimposing waveform slices from a
multi-bit acquisition. To use DDR eye diagrams, option R&S RTP-K91 is required.
13.23.4.1 Calculation and display of DDR eye diagrams
The R&S RTP with option R&S RTP-K91 generates eye diagrams for the DDR signals.
To build DDR eyes, the oscilloscope acquires a long waveform containing many bits.
The instrument uses the clock reference provided by the DQS channel to cut the wave-
form into slices of 1-bit length, and superimposes the individual slices. The superim-
posed slices of consecutive bits build the DDR eye. The clock reference defines the
position of the individual data bits on the time axis, and so it provides the necessary
timing marks to align and superimpose the waveform slices.
You can define up to four eye diagrams and configure them independently. Each eye
diagram is shown in a separate display diagram, which has its own signal icon. You
can move and minimize eye diagrams like any waveform diagram and analyze all eye
diagrams in parallel.
The following analysis functions are available for eye diagrams:
●
Cursor measurements
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Automatic eye measurements
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Histograms
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Zoom
13.23.4.2 Eye diagram setup
This chapter describes the configuration of eye diagrams.
The configuration of an eye diagram mainly consists of the selection and setup of the
input source and timing reference source. You can also adjust display settings and
restrict the segments that contribute to the eye generation by various means.
You can configure and analyze up to four independent eye diagrams in parallel. Dia-
gram "Eye1" is shortly named "E1", and so on.
The "DDR Eye Diagram" dialog box provides four tabs with all settings that are
required to configure eye diagrams.
Basic setup
Access: [App Cockpit]> "Analysis" > "DDR Eye" > "Setup" tab
In the "Setup" tab, you configure the source, the timing reference, and horizontal scale
settings of the eye diagram. The vertical scale of the eye diagram is coupled to the ver-
tical scale of the data source.
DDR (option R&S
RTP-K91/K93 )
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