Preparing for Signal Quality Analysis
1
DSOX4USBSQ USB 2.0 Signal Quality Analysis Application Electrical Testing Notes
17
vendor). Therefore, an automatic driver stack switching function has been
implemented into the Hi- speed Electrical Test Tool for easy switching
between the proprietary EHCI driver stack and that from Microsoft.
Upon invocation of the HS Electrical Test Tool software, the driver stack
will automatically switch to the Intel proprietary EHCI driver stack.
Upon exit of the HS Electrical Test Tool software, the driver stack will
automatically switch to the Microsoft EHCI driver stack.
Additional Set Up for Signal Quality Compliance Testing
When performing USB 2.0 signal quality compliance testing (instead of
testing the signal quality of real- world packets), be sure to take these
additional set up steps:
1
Turn on the oscilloscope to allow 30 minutes of warm up time prior to
use.
2
When performing signal quality compliance testing, if the ambient
temperature has changed more than 5 degrees from the previous
calibration, perform the user calibration procedure built into the
oscilloscope.
3
Compensate the passive probes (see the oscilloscope
user's guide
).
4
Calibrate all the probes.
