Ceyear 4051 Series, Руководство пользователя

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5 Menu
5.2. Description of menu
375
When set to Gate ON, an FFT is performed whenever the specified gate conditions are satisfied. This is an
FFT measurement which begins when the predefined conditions are satisfied. Since the time period of an FFT
is approximately 2.57/RBW, you get a measurement which starts under predefined conditions and takes place
over a predefined period. So, in essence, this is a gated measurement.
Gated FFT cannot be done in zero span. So in zero span, the Gated LO and Video methods are used. Data is
still only taken while the specified gate parameters are satisfied, so the gate settings do impact when data is
acquired.
● Key path:
【
Sweep
】
, [Gate
▶
], [Gate Setup
▶
], [Gate Method
▶
], [FFT] on the front panel.
● Remote Command:
[:sense]:sweep:egate:method FFT
[:sense]:sweep:egate:method?
● Examples:
:SWE:EGAT:METH FFT
:SWE:EGAT:METH?
[Control Edge Level]
● Menu description: set the method of controlling the gating function.
— Edge
When the selected edge (positive or negative edge) of the trigger signal arrives, whether the Gate is ON is
determined by the subsequent gate delay and gate length (both can be set by the menu). The Gate is ON
whenever the trigger event arrives and the gate delay time has passed. During the gate length, the signal
passes through; when the gate length ends, the signal is blocked. In general, for edge triggering, the trigger
signal is an TTL periodic signal, whose positive and negative edges are synchronous with those of the
measured pulse signal. Gate delay time refers to the time during which the signal/spectrum analyzer needs to
wait from the trigger event to Gate ON.
— Level
When the gate signal has achieved a certain level (high level or low level. In signal/spectrum analyzer,
positive polarity indicates high level; and negative polarity indicates low level), the signal passes through; and
when the gate signal fails to achieve specified level, the signal is blocked. In Level triggering, the Gate Delay
and Gate Length parameters are void.
●
Key path: 【 Sweep 】 , [Gate ▶ ], [Gate Setup ▶ ], [Control Edge Level] on the front panel.
●
Status saved: saved in the instrument status.
●
Factory preset: Edge.
● Remote Command:
[:sense]:sweep:egate:control EDGE|level
[:sense]:sweep:egate:control?
● Examples:
:SWE:EGAT:CONT EDGE
:SWE:EGAT:CONT?
[Gate Holdoff On Off]