X-Stream Operator’s Manual
WM-OM-E Rev I 365
(horizontal lines) are displayed in the "after" picture. The ML Markers indicate the location of the
ideal PRML sample values based on the DDA’s channel emulation. The Level Markers indicate the
vertical position of the PRML levels based on the amplitude of the acquired PRML signal.
Selecting the Waveform Section to Be Analyzed
For the Analog Compare and Channel Emulation channel analysis methods, you can specify
selective areas of the head signal for analysis by using the Analyze Region cursors or the drive’s
Read Gate signal, or both.
As discussed above, it is important for the DDA to be able to analyze the VCO Synch signal at the
beginning of the region it is analyzing. If Read Gate is used to determine which head signal sections
to analyze, this will not be a problem, since the DDA will use Read Gate to identify the location of
VCO Synch. If Read Gate is not used, it is important, by means of the Analyze Region cursors, that
the beginning of the head signal section analyzed be very near the beginning of VCO Synch.
The following figures show the areas of the waveform to be analyzed, with the different
combinations of the Analyze Region cursors or Read Gate, or both, enabled. The Analyze Region
cursors, if enabled, generally specify the outer-most boundaries of the data to be analyzed. They
are particularly useful if Read Gate is not available or if only a subset of several Read Gate true
sections captured is to be analyzed --- for example, a single sector within several captured, or
excluding the ID field. Within the area designated by the markers, if Read Gate is specified, only the
regions of the Head Signal during which Read Gate is true are analyzed (as shown in Case 1) while
all others are ignored.
Case 1: Only Read Gate True regions are analyzed
Similarly, if Analyze Region is disabled and Read Gate enabled, the area of the Head Signal during
which Read Gate is true is analyzed, as shown in sections A, B, C, D, and E in Case 2
Case 2: Head Signal Read Gate True regions analyzed
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