Uni-Trend UT4000 Series, Руководство пользователя

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33
UNI-T
®
UT4000 User Manual
Definitions
1.
Trigger source
: This means the signal for trigger. Trigger can be obtained from
various sources : Input channel (CH1, CH2), external trigger (EXT, EXT/5), grid,
CH1 and CH2 alternate.
„
Input Channel
: The most common trigger source is input channel (choose
CH1 or CH2). The selected trigger source can operate normally whether the
input is displayed or not.
„
External Trigger
: This type of trigger source can be directly input through
the external trigger input terminal. For example, you can use an external clock
or the signal from a circuit to be tested as the trigger source. Both EXT and
EXT/5 trigger sources use external trigger signals from the EXT TRIG adaptor.
EXT can use the signals directly. You can use EXT within the trigger level
range of –3V and +3V. EXT/5 divide the trigger by 5. As a result, trigger range
is extended to –15V to +15V, enabling the oscilloscope to trigger at a large
signal.
„
Grid
: means the grid power source. This trigger mode is suitable for
observing signals related to the grid
⎯
e.g. the correlation between lighting
equipment and power source equipment
⎯
to achieve stable synchronization.
2.
Trigger mode
: To cause the digital storage oscilloscope to generate a trigger signal.
This oscilloscope offers three trigger modes for selection : auto, normal and single.
„
Auto Trigger
: The system will sample waveform data automatically when
there is no trigger signal input. The scan baseline is shown on the display.
When the trigger signal is generated, it automatically turns to trigger scan for
signal synchronization.
Note :
When time base of the scan range is set to 50ms/div or slower, the
“Auto” mode is a continuous scanning process.
„
Normal Trigger
: In this mode, your oscilloscope samples waveforms only
when triggering conditions are met. The system stops acquiring data and waits
when there is no trigger signal. When the trigger signal is generated, trigger
scan occurs.
„
Single Trigger
: In this mode, you only have to press the “Run” button once
and the oscilloscope will wait for trigger. One sampling will occur and the
acquired waveform will be displayed when the digital storage oscilloscope
detects a trigger. Then trigger will stop.
3.
Trigger coupling
: Trigger coupling determines which quantities of the signal are
transmitted to the trigger circuit. Coupling modes are DC, AC, low frequency
suppression and high frequency suppression.
„
DC
: Allowing all quantities to pass.
„
AC
: Intercepting DC quantities and attenuating signals under 10Hz.
„
Low Frequency Suppression
: Intercepting DC quantities and attenuating low
frequency quantities under 80kHz.