Author Topic: Agilent/Keysight InfiniiVision Voltage diplayed when moving the beam vertically  (Read 1248 times)

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Offline paschulke2

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I had the luck to get a Keysight DSO-X2024A at very good price and I am very happy with it.

There is one minor quirk I (long time Tektronix user) don't understand: When I move a beam up, a negative voltage is displayed. I would have expected a positive voltage. Of course ( ;)) I read the manual, which says:

Quote
1 Turn the small vertical position knob to move the channel's waveform up or down on the display.

The voltage value momentarily displayed in the upper right portion of the display represents the voltage difference between the vertical center of the display and the ground level ( ) icon. It also represents the voltage at the vertical center of the display if vertical expansion is set to expand about ground (see “To choose "expand about" center or ground" on page 47).

Ah ja. What?

Why a negative voltage for a move in positive direction? Can someone enlighten me?
« Last Edit: September 26, 2015, 02:09:54 pm by paschulke2 »
 

Online HighVoltage

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I guess it is just a way of definition.
In this case it is how much you have to correct, to get back to zero.

All my Agilent scopes do the same.
But not only in the offset of the vertical voltage axis, but also the horizontal time axis
Here are two pictures of horizontal and vertical moving.
Interestingly it is captured with the screen shot.
 
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Offline Wuerstchenhund

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Why a negative voltage for a move in positive direction? Can someone enlighten me?

It's simple, the old scope probably showed the vertical distance in Volts between the midline (reference) and the trace while the new scope shows the vertical distance between the trace (reference) and the midline  ;)
 

Offline paschulke2

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The Tektronix Scopes I know have an "offset" and a "Pos." setting. I have just checked it with a DPO2024B: The offset behaves exactly like the vertical position on the Keysight. I guess I've never used the "offset" setting on a Tektronix Scope.

To me this is bit like a Multimeter that displays the voltage at the "COM" input referenced to "V/Ohm" … just a matter of definition ;)

 


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