GW Instek GDS-800 Series User Manual User Manual
Page 31
GDS-800 Series Digital Storage Oscilloscope Operation Manual
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: Switch off frequency reject mode.
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Noise Rej On/Off: Press F4 softkey to enable noise reject mode. Noise reject
mode provides lower DC sensitivity. It requires additional signal amplitude for
stable triggering, reducing the change of falsely triggering on noise.
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Previous Menu: Back to previous menu.
Video Triggering
Press F1 softkey can select video triggering.
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Type Video: The video trigger gives user a variety of selections for triggering on
video signals: the selection of NTSC, PAL or SECAM video signal; polarity; line,
field 1 or field 2.
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SOURCE: Select the channel 1 or channel 2 as trigger source.
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Standard NSTC/PAL/SECAM: Press F3 softkey to select predefined setups
(NSTC, PAL or SECAM). NSTC has a line rate of 525 lines per frame and a field
rate of 60Hz. PAL and SECAM have a line rate of 625 lines per frame and a field
rate of 50Hz.
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Polarity
: The video trigger can trigger on the negative- going
sync pulses (default). If need to trigger on positive-going sync of a signal, simply
invert the signal by pressing F4 softkey again.
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Field 1/Field 2/Line:
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Field 1: Press F5 softkey to trigger on field 1 of the video signal. Rotate the
VARIABLE knob to display the specific line. (The adjustable line range for NSTC:
1~263; for PAL/SECAM: 1~313)