Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 232 / 813

Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.70 E-6
Define Time Gate
The Define Time Gate defines the properties of the time gate used to eliminate unwanted
responses that appear on the time domain transform.
•
Start and Stop or Center and Span define the size of the time gate.
•
The filter Type defines what occurs to the data in the specific time region. A Band Pass filter
passes all information in the specified time region and rejects everything else. A Notch filter
rejects all information in the specified time region and passes everything else.
•
The Gate Shape panel visualizes how the time gate will affect a constant function after
transformation back into the frequency domain. The selected window is applied to the active
trace. The two red vertical lines represent the
Start and Stop values defining the size of the time
gate.
•
If an Arbitrary Gate Shape (Dolph-Chebychev) window is selected, the Arbitrary Sidelobe Level
can be set below the Gate Shape diagrams.
Use the paste marker list for convenient entry of Start and Stop values.
•
Comparison of time gates
The properties of the time gates are analogous to the properties of the frequency domain windows. The
following table gives an overview:
Window Sidelobe suppression Passband
ripple
Best for...
Steepest Edges
(Rectangle)
13 dB 0.547 dB Eliminate small distortions in the vicinity of the
useful signal, if demands on amplitude accuracy
are low
Steep Edges
(Hamming)
43 dB 0.019 dB Good compromise between edge steepness and
sidelobe suppression
Normal Gate (Hann) 32 dB 0.032 dB Good compromise between edge steepness and
sidelobe suppression