Keysight Technologies DSO-X 2014A, Руководство пользователя

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Mask Testing
15
Keysight InfiniiVision 2000 X-Series Oscilloscopes User's Guide 239
• The Y1 setup command specifies the vertical location of the x,y graph's y origin.
• The XDELta setup command specifies the amount of time associated with each
x unit.
• The Y2 setup command is the vertical location of the x,y graph's y=1 value (so
in effect, Y2 – Y1 is the YDELta value).
For example:
• With a graticule whose trigger position is 10 ns (before a center screen
reference) and whose ground reference (offset) is 2 V below the center of the
screen, to place the mask region's x,y graph's origin at center screen, you would
set X1 = 10 ns and Y1 = 2 V.
• If the XDELta parameter is set to 5 ns and Y2 is set to 4 V, a mask region whose
vertices are (-1, 1), (1, 1), (1, -1), and (-1, -1) goes from 5 ns to 15 ns and from
0 V to 4 V.
• If you move the mask region's x,y graph origin to the t=0 and V=0 location by
setting X1 = 0 and Y1 = 0, the same vertices define a region that goes from
-5 ns to 5 ns and from -2 V to 2 V.
How is mask testing done?
InfiniiVision oscilloscopes start mask testing by creating a database that is 200 x
640 for the waveform viewing area. Each location in the array is designated as
either a violation or a pass area. Each time a data point from a waveform occurs in
a violation area a failure is logged. If Test All was selected, every active analog
channel is tested against the mask database for each acquisition. Over 2 billion
failures can be logged per-channel. The number of acquisitions tested is also
logged and displayed as "# of Tests".
The mask file allows greater resolution than the 200 X 640 database. Some
quantization of data occurs to reduce the mask file data for display on-screen.
NOTE
Although a mask can have up to 8 regions, in any given vertical column, it is only possible to
define 4 regions. When there are 4 regions in a vertical column, one region must be tied to the
top (using the MAX y value) and one must be tied to the bottom (using the MIN y value).