Racal Instruments 3156B, Руководство пользователя

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3156B User Manual
Racal Instrument © 2005 Getting Started 1-21
Continuous
In continuous modulation, the carrier waveform is modulated
continuously. Two conditions are required for the 3156B to generate
continuous modulation: 1) Output is on and 2) Output is enabled by
either a software or hardware enable command. Modulation can be
stopped (always at the end of the last cycle of the modulating
waveform) with a software enable off command. Chapter 3 lists the
various options of enabling and disabling the output waveform in the
various run modes and enable sources. When not enabled, the 3156B
outputs carrier waveform (sine) with frequency value defined by the
carrier frequency parameter.
Triggered
In triggered mode, the Model 3156B circuits are armed to generate a
single cycle of modulated waveform. The trigger circuit is sensitive to
transitions at the trigger input. Select between positive or negative
transitions to trigger the instrument. You may also program the trigger
level to the desired threshold level.
When not enabled, the 3156B outputs carrier waveform (sine) with
frequency value defined by the carrier frequency parameter. When
enabled, the generator outputs one modulation cycle and resumes
carrier frequency at the end of the modulating waveform.
Two conditions are required for the 3156B to generate triggered
modulation: 1) Output is on and 2) Output is enabled by either a
software or hardware enable command. The Model 3156B can be
enabled from a number of sources: trigger signal from a front panel
connector, trigger signal on one of the VXI backplane TTLTRG<n> or
software command.
Delayed Trigger
The delayed trigger modulation run mode is exactly the same as the
trigger mode except a programmable delay inhibits the modulation for
a programmable period after a valid trigger. The delay time defines the
time that will lapse from a valid trigger (hardware or software) to the
first modulation cycle. The delay is programmable in steps of 20ns
from 500ns to 21 seconds. The delayed trigger can be applied to all
modulation run modes: continuous, trigger and burst.
Four conditions are required for the 3156B to output waveforms in
delayed trigger modulation run mode: 1) Output is on 2) Output is
enabled by either a software or hardware enable command 3) Delayed
trigger is on and 4) Delay value is programmed.