Instructions

Digital Storage Oscilloscope 24
9. Press the Show-Only softkey to select to display FFT operation results only and
not display the source channel.
Note:
 Signals with DC components or deviation would cause an error or deviation of the
FFT waveform components. To reduce the DC components, set the Channel Coupling
to AC.
 To reduce the random noise and aliasing frequency components of repetitive or
single pulse, set the Acquisition of the oscilloscope to Average.
Using Cursors to measure FFT waveform
To make cursor measurements, press the Cursors button to turn the cursors, and then
press the Mode softkey to select Manual or Track, Use the AX and BX cursors to
measure frequency values and the difference between two frequency values (BX-AX).
Use the AY and BY cursors to measure amplitude in dB and difference in amplitude
(BY-AY).
2.7 Trigger System
The trigger determines when the oscilloscope begins to acquire data and display a
waveform. Once a trigger is properly set up, the oscilloscope can convert unstable
displays or blank screens to meaningful waveforms. Here introduce some basic
concepts about trigger.
Trigger Source: The trigger can be generated with multiple sources. The most
common one is the input channel (CH1~CH4). Whether the input signal is displayed or
not, it can trigger normal operations. Also the trigger source can be any signal
connected to an external trigger channel (only for Edge trigger).
Trigger Mode: You can select the Auto or Normal mode to define how the oscilloscope
acquires data when it does not detect a trigger condition. Auto Mode performs the
acquisition freely in absence of valid trigger. It allows the generation of untriggered
waveforms with the time base set to 100ms/div or slower. Normal Mode updates the
displayed waveforms only when the oscilloscope detects a valid trigger condition.