Test Equipment Depot GOS-620 Operation page 24

(3)Functions of TRIG LEVEL control knob and SLOPE button:
A sweep triggering is developed when the trigger source signal crosses a preset threshold level. Rotate TRIG LEVEL control
knob to vary the threshold level. In the "+" direction, the trigger threshold shifts to a more positive value, and in the
"-" direction, the trigger threshold shifts to a more negative value. When set the control knob in the center, the threshold level
will be on the average of the signal used as the trigger source.
Adjust TRIG LEVEL control knob for the desired start point of sweep on a waveform. On sine wave signals, the phase at which
sweep begins is variable. Note that if rotate TRIG LEVEL control knob toward its extreme "+" or "-", no sweep will be
developed in the NORM trigger mode because the trigger threshold exceeds the peak amplitude of the sync signal.
When set TRIG SLOPE button to the (+) position (up), the sweep is developed form the trigger source waveform as it crosses
the threshold level in a positive-going direction. When set TRIG SLOPE button to the (-) position (down), a sweep triggering is
developed from the trigger source waveform as it crosses the threshold level in a negative-going direction. The slope (polarity)
trigger signal as shown in Figure 5-4.
Fig. 5-4
(4) Function of TRIG ALT button:
The TRIG ALT button is used to select alternate triggering and display the selected DUAL-trace of VERT MODE (the switch
control knob CH1, CH2, DUAL and ADD modes). In the alternate trigger mode (when select dual-trace operation), the trigger
source alternates between CH1 and CH2 with each sweep. This is convenient for checking amplitudes, wave-shape, or
waveform period measurements, and even permits simultaneously observing two waveforms which are not related to frequency
or period. However, this setting is not suitable for phase or timing comparison measurements. For such measurements, both
traces must be triggered by the same sync signal.
If press both CHOP and TRIG ALT buttons during dual-trace operation, synchronization of the display is not possible because
the chopping signal will be triggered. Use ALT mode itself, or select CH1 or CH2 as trigger source.
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