User`s guide

Appendix C – SIA-3000™ Calibration
Calibration Options
The Calibration selection is used to access the instrument's calibration options and has a separate
button for each calibration option. The instrument firmware version is used by GigaView™ to
determine which features the instruments can support and is displayed at the top of the dialog window.
**Make sure matched cables are used in all calibrations.**
There are 5 distinct user calibrations that need to be performed in order (three are optional):
• Timer Calibration – Affects RJ noise floor, relative accuracy of all time measurements.
• Oscilloscope/Arming Calibration – Oscilloscope delay settings, Arm Delay settings.
Always perform this calibration after the Timer Calibration. Additionally, if “Deskew
Calibration w/DC Offset” fails, you should run this step prior to Deskew.
• Deskew Calibration with DC Offset – Absolute measured values, internal channel skews,
channel-to-channel skew and DC voltage offset.
• Deskew Calibration only – (Do not perform if Deskew Calibration with DC Offset has
been performed) Absolute measured values, internal channel skews and channel-to-
channel skew.
• Manual Channel Skews – Channel-to-channel skew.
Verify Calibration
This verification does NOT change any calibration values, it only checks them and suggests
whether or not a calibration should be performed. As the next step after verification, a
calibration may need to be performed.
After selecting verify calibration, a pop up menu will appear. Press Begin and another menu will
appear with directions to follow for verification. Using the
WAVECREST supplied matched
length SMA cable pair, connect between the calibration outputs and the channel input specified
in the pop-up window. A new window will pop-up for each channel in the system. You will have
to move the cables to the next channel following the on screen instructions. Pressing Skip will
not test that channel and will advance to the next channel.
After completion of the verification, the results window will display pass/fail results and values
for the simple tests that were performed. If any channel fails, calibration is recommended. Or, if
the values shown are higher than the values you expect to see in your measurements, you may
want to continue with calibration. The verification measures the
SIA-3000 900MHz
calibration output using the Histogram and High Frequency Modulation tools. It checks the 1-
sigma and mean of a period histogram and looks at the magnitude of periodic components from
an FFT. A calibration is recommended and a note will appear in the Results window if the 1-
sigma or any single accumulated frequency component is greater than 3ps or the absolute mean
is +-30ps from its expected value.
© WAVECREST Corporation 2005 Appendix C
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