LeCroy DDA 7 Zi series, Operator'S Manual

Page: 401 / 544

Operator's Manual
WP700Zi-OM-E-RevA
400
Mask Margin
1. Touch inside the X field and enter a value from 0 to 100%. As you enlarge the mask's X margin, you
lengthen the horizontal dimension, bringing the mask closer to your waveform. Consequently, you will have
more failures.
2. Touch inside the Y field and enter a value from 0 to 100%. As you enlarge the mask's Y margin, you widen
the vertical dimension, bringing the mask closer to your waveform. Consequently, you will have more
failures.
3. Touch the Vertical Auto fit checkbox if you want to scale the eye pattern.
Note: The vertical autofit function sets the scaling of the eye pattern so that the one level is at the second
vertical division above center, and the zero level is at the second division below center. The Vertical Auto fit
checkbox is automatically checked or unchecked depending on the Signal Type that you selected. For example,
when an absolute mask like XAUI is selected, the
Vertical Auto fit box is unchecked; but, it is checked for a
normalized mask like FC1063.
Scaling for absolute mask signals is accomplished by setting the vertical scale of the input signal.
Testing
1. Touch the Mask Violation Locator tab to display the mask testing dialog
2. Touch the On checkbox to begin testing the signal bits against the selected mask.
3. Failed bits are displayed in a table and as a waveform in the lower grid. The scale of the lower grid in which
the failed bit waveform is set by the
Bits in Locator field. The failed bit is centered around the middle two
divisions and the vertical scale is the same as the eye pattern.
4. Touch the Stop On Error checkbox if you want to halt testing when an error occurs. But testing will
continue until the end of the acquired waveform is reached.
5. Touch the Show Location checkbox, then touch inside the Show field and select All or Near X-Y from the
pop-up menu. All means that all failures will be shown, regardless of where they occur in the eye pattern.
Near X-Y means that if you select a failure marker, either by touching the marker on the waveform or by
touching the bit number in the Failures list, only the subsequent failures near the selected marker will be
shown.
Note: The X and Y coordinates indicate the position of the selected failure on a grid normalized to one, read
from left to right and top to bottom.
6. Touch inside the N Failures field and, using the pop-up keypad, enter the number of failures after which
data accumulation will end, up to 10,000. Multiple failures can occur on each bit, so the value of N failures
will always be equal to or greater than the number of failed bits.
7. Touch inside the Bits in Locater field and, using the pop-up keypad, enter the number of bits to be
displayed in the bad bits trace. This trace shows the part of the waveform that violates the mask.
Bit Error Rate
1. Press the Serial Data Analyzer (SDA) button on the Quick Access toolbar; or, touch Analysis in the menu
bar, then Serial Data in the drop-down menu. The display defaults to the "Scope" dialog, which enables
you to set up SDA measurements while you continue to view currently displayed waveforms.
2. Touch the BER button. This brings you to the BER setup dialog.
3. Under Pattern , touch inside the Method field and select Pattern (expected bit pattern in the data stream),
PRBS (a pseudo-random bit sequence), or File (a saved user ASCII hex file).
4. If you chose Pattern , use the pop-up keyboard to enter a hexadecimal number as a bit pattern.
If you chose PRBS , touch inside the PRBS Sequence field and select a bit sequence from the pop-up
menu. The digit at the end of PRBSx represents the number of shift registers to be used in the generation
of the pseudo-random bit sequence used for BER testing. The sequences generated for each n value are
as described in ITU-O.150.
If you chose File , enter the path to the file, using the pop-up keyboard; or, touch the Browse button and
navigate to the file.