Keysight Technologies N5991ST3A SATA, Руководство пользователя

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Keysight N5991 SATA Test Automation Software Platform User Guide 73
Receiver Tests 5
Rcvr Data Rate Deviation Tolerance Test
This test is available for all data rates.
Purpose and Method
This test assures that the DUT can still work with the maximum data rate
deviation (positive and negative).
The test starts with the value of '0' ppm and decreases the data rate
linearly with Deviation Step Size value until the value of Min Deviation is
reached. When an error is found, it jumps back to the previous passed test
point and starts stepping down again with the new Deviation Step Size
value until an error is found. The minimum passed value is the final test
point that returns no error. The step size value used for the larger steps at
the beginning of this test depends on the relation between Deviation Step
Size and Min Deviation. It is calculated as:
For the default values of Deviation Step Size = 10 ppm and Min Deviation =
–1000 ppm, the value of the initial step size is 100 ppm. Once the
minimum passed value has been found, the test performs the same
method for the higher limit with Max Deviation and positive steps instead
of Min Deviation and negative steps. This algorithm avoids initializing a
DUT repeatedly, which makes the DUT come out of loopback mode. If an
error occurs, it requires fewer test points than a simple linear search.
Connection Diagram
Refer to Figure 20 (M8020A) and Figure 21 (M8040A)
Parameters in Expert Mode
• Number of Allowed Frame Errors: The number of frame errors that are
allowed. The default value is '0'.
• Number of Frames: The number of frames used for frame error
measurement.
• Deviation Step Size: The minimum distance between two tested data
rate deviations.
• Min Deviation: If no error occurs, this is the lowest data rate deviation
that is tested.
• Max Deviation If no error occurs, this is the highest data rate deviation
that is tested.