Selecting Channels
TDS 620A, 640A, & 644A User Manual
To selecting a channel:
Pressing CH 1, CH 2, CH 3 (AUX 1 on the TDS 620A & TDS 524A), or CH 4
(AUX 2 on the TDS 620A & TDS 524A) turns the channel on if it is not al-
ready on.
You do not use the channel selection buttons when triggering. Instead you
select the trigger source in the Main Trigger menu or Delayed Trigger menu.
Removing Waveforms From the Display
The WAVEFORM OFF button turns OFF the display of the selected channel
waveform. It will also remove from the display any automated measurements
being made on that waveform.
When you turn off a waveform, the digitizing oscilloscope automatically se-
lects the next highest priority waveform. Figure 3-72 shows how the oscillo-
scope prioritizes waveforms.
1. CH1
2. CH2
3. CH3 (AUX 1 on the TDS 620A & TDS 524A)
4. CH4 (AUX 2 on the TDS 620A & TDS 524A)
5. MATH1
6. MATH2
7. MATH3
8. REF1
9. REF2
10. REF3
11. REF4
Figure 3-72: Waveform Selection Priority
If you are turning off more than one waveform and you start by turning off a
channel waveform, all channels will be turned off before going to the MORE
waveforms. If you start by turning off the MORE waveforms, all the MORE
waveforms will be turned off before going to the channel waveforms.
If you turn off a channel that is a trigger source, it continues to be the trigger
source even though the waveform is not displayed.
See

Saving and Recalling Waveforms,

on page 3-133.
See

Waveform Math,

on page 3-159.
Operation
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