Measuring signals
&
□ st®p 4: Push the CURSORS knob in to seiect the other cursor and
position it on the upper point,
[~| Step 5: Note the A volts (change or difference in volts) readout in the
upper left corner of the display.
Figure 3-31 shows a typical Peak-to-peak voltage measurement.
Figure 3-31: Peak-to-Peak Measurement
Measuring Voitages in Reference to Ground
When a signal is DC coupled at the input, you can measure DC voltage
levels, DC components of an AC signal (Figure 3-32), or other voltage levels
in reference to ground (Figure 3-33). The procedure varies slightly depend
ing on whether you use graticule lines or cursors to measure the DC level.
Graticule lines:
F I Step 1: Set the input coupling to GND and the trigger mode to P-P
AUTO to display a flat trace on screen.
1~1 Step 2: Align the trace with a horizontal graticule line. This line is now
the ground reference point.
â–¡ Step 3: Set the input coupling to DC.
P I Step 4: The amount of vertical offset is the DC component.
Cursors:
F~1 Step 1: Set the oscilloscope to STORE.
F I Step 2: Set the input coupling to GND and wait a couple of seconds.
The oscilloscope will now recognize this point as ground and place a
small dot at the left side of the screen. (This dot may not be readily
apparent if you have a fiat line trace on screen.)
F I Step 3: Set the input coupling to DC.
2221A User Manual
3-33