284
Mask testing consists of two tasks: signal violation detection and pass/fail testing. Signal violation
detection lets you test communications signals for time or amplitude violations against a
predefined mask. Each mask consists of one or more polygonal regions called segments. The
signal waveform data should stay outside of the segments defined by the mask. Any signal data
that occurs inside a mask segment is called a mask segment violation or "hit."
You can select from any of the included standard telecommunications masks, or you can define
your own custom masks. Selecting a mask automatically sets the instrument communications
triggers to properly display most communication signals in the mask.
Pass/Fail testing defines the mask testing parameters, including the number of waveforms to test,
how many mask hits are allowed before failing a test, setting a mask margin tolerance value, and
what action to perform upon the completion or failure of a test.
Communication triggering enables you to trigger on and display waveforms for industry-standard
communications signals. See Mask Types and Standards on page 169 for a list of the supported
standards on which you can trigger.
Automatic communication signal measurements enable you to make automatic measurements on
communications signals. See the Communication Measurement on page 161 tab in the
Measurement setup window for the available measurements.
The Serial Mask Testing key features are:
 Predefined masks for testing or triggering on industry-standard signals, such as ITU-T G.703,
ANSI T1.102, Fibre Channel, Ethernet, Video, SONET, Rapid IO, USB, IEEE 1394b, OIF
Standards and their subsets
 Autoset, which quickly adjusts the instrument’s vertical and horizontal controls to display a
waveform in a mask
 Autofit, which positions the signal on each acquisition to minimize mask segment hits
 Mask margins, which allow you to adjust the default mask margin tolerances
 Pass/Fail testing to continuously test a specified number of waveforms against a mask
 A mask editor for creating, saving, and recalling user-defined masks
 Waveform database technology to perform mask testing based on waveforms accumulated in
a database, rather than a single waveform stored in acquisition memory
 Communications triggers to trigger the instrument on industry-standard communications
signals
 Automatic measurements on communications signals
Note
If a standard listed in this manual is not available on your instrument, it is because the
configuration or bandwidth of your instrument cannot test that standard.
Although the TDS5000B Series instruments are not calibrated optical reference receivers, you can
use them with mask testing to evaluate general optical signal characteristics and wave shape, using
an external O/E converter.
Mask Key Points
There are a number of mask test key points to be aware of prior to using, editing, or creating a
mask.
Mask Testing
To Next Page
Loading...
Need help?
General
