Agilent Technologies X Series Manual page 552

Sweep/Control
Turning Gate View off returns the analyzer to the Normal measurement view.
In the Swept SA, the normal measurement view is the single-window Swept SA view. When returning to
this view, the Swept SA measurement returns to the Span it was in before entering Gate View (even if
that is Zero Span).
The Gate View window is triggered from the Gate Source, with zero trigger delay. Also, when updating
the Gate View window, the Gate itself must not operate. So it is internally shut off while the gate view
window is being updated. For the Swept SA measurement, this means that the Gate is internally shut off
whenever the gate view window is displayed. The measurement bar and softkeys continue to show the
Trigger source for the main sweep window and give no indication that the Gate is shut off or that the
Gate View window is triggered from the Gate Source.
When in Gate View, vertical lines are displayed in the Gate View window as follows:
• Green lines are displayed at the gate edges as follows: in Edge Gate, a line is shown for Delay and
one for the end of the Gate period (defined by Length, even in FFT. In Level Gate a line is shown
only for Delay. You can adjust the position of the green lines by adjusting the gate length and the gate
delay. These lines update in the Gate View window as the active function changes, even if the
window is not being updated. In Gated LO and Gated Video, these lines are positioned relative to the
delay reference line (not relative to 0 time). In Gated FFT, their location is relative to the left edge of
the screen.
• A blue line is displayed showing the delay reference, that is, the reference point for the Gate Delay
within the Zero Span window. The blue line represents where (in time) the effective location of the
gate start would be if the gate were programmed to zero delay.
• The second blue line is labeled "MIN FAST" as shown in the figure above because it represents the
minimum Gate Delay for fast Gated LO operation. This line is only displayed in Gated LO. You
cannot scroll (knob) or decrement (down key) the Gate Delay to less than that represented by the
position of this line, it can only be set below this position manually, although once there it can be
moved freely with the knob while below the line.
• A yellow line in the Gated Video case only, is displayed at B
(bucket) length for the swept trace, which is given by the sweep time for that trace divided by number
of Points – 1. So it is referenced to 0 time, not to the delay reference. This line is labeled NEXT PT (it
is not shown in the figure above because the figure above is for Gated LO). The yellow line
represents the edge of a display point (bucket). Normally in Gated Video, the bucket length must be
selected so that it exceeds the off time of the burst. There is another way to use the analyzer in Gated
Video measurements, and that is to set the bucket width much shorter than the off time of the burst.
Then use the Max Hold trace function to fill in "missing" buckets more slowly. This allows you to see
some of the patterns of the Gated Video results earlier, though seeing a completely filled-in spectrum
later.
Gate View Sweep Time
Controls the sweep time in the Gate View window. To provide an optimal view of the gate signal, the
analyzer initializes Gate View Sweep Time based on the current settings of Gate Delay and Gate Length.
Key Path
552
Sweep/Control, Gate
, where B is the display point
length length