Agilent Technologies E5070B, Руководство пользователя

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346 Chapter 9
Analysis in Time Domain (Option 010)
Deleting Unnecessary Data in Time Domain (gating)
Operational procedure
Step 1. Press (or ) and (or ) to activate the trace for
which you want to set the gate type.
Step 2. - Press
Gating
to display the “Gating” menu.
Step 3. Press
Type
to toggle between band pass (
Bandpass
) and notch (
Notch
).
Setting gate shape
The gate is a filter whose shape looks like a band pass filter. There are several parameters
that indicate the gate shape. Figure 9-9 shows their definitions.
Figure 9-9 Parameters of gate shape
Table 9-1 compares the characteristics according to the gate shape. When the shape is
“minimum,” the cutoff time is shorter and the response is deleted abruptly, but the sidelobe
level and band pass ripples become larger. When it is “maximum,” cutoff is gentler, but the
sidelobe level and the band pass ripple become smaller. The minimum gate span in Table
9-1 is the minimum gate range you can set. This value is defined as the minimum gate span
necessary for the existence of the pass band and is equal to 2 times the cutoff time.
Table 9-6 Comparison of gate characteristics
Gate shape Passband ripple Sidelobe level Cutoff time Minimum gate span
Minimum
±
0.13 dB
−
48 dB 1.4/frequency span 2.8/frequency span
Normal
±
0.01 dB
−
68 dB 2.8/frequency span 5.6/frequency span
Wide
±
0.01 dB
−
57 dB 4.4/frequency span 8.8/frequency span
Maximum
±
0.01 dB
−
70 dB 12.7/frequency span 25.4/frequency span