Selecting Gate Shape - Agilent Technologies 8719ES User Manual

Making Time Domain Measurements
Gating
Figure 3-27 Gate Shape

Selecting Gate Shape

The four gate shapes available are listed in
flatness, cutoff rate, and sidelobe levels.
Table 3-4 Gate Characteristics
Gate Shape Passband Ripple
Gate Span
Minimum
Normal
Wide
Maximum
Note: With 1601 frequency points, gating is available only in the bandpass mode.
The passband ripple and sidelobe levels are descriptive of the gate shape. The cutoff time
is the time between the stop time (−6 dB on the filter skirt) and the peak of the first
sidelobe, and is equal on the left and right side skirts of the filter. As shown in
the minimum gate span is just twice the cutoff time because it has no passband. Always
choose a gate span wider than the minimum. For most applications, do not be concerned
about the minimum gate span, simply use the knob to position the gate markers around
the desired portion of the time domain trace.
3-36
Sidelobe Levels
±0.10 dB −48 dB
±0.10 dB −68 dB
±0.10 dB −57 dB
±0.10 dB −70 dB
Table 3-4. Each gate has a different passband
Cutoff Time
1.4/Freq Span
2.8/Freq Span
4.4/Freq Span
12.7/Freq Span
Minimum Gate Span
2.8/Freq Span
5.6/Freq Span
8.8/Freq Span
25.4/Freq Span
Table 3-4,