Agilent Technologies 54622A User Manual page 108

MegaZoom Concepts and Oscilloscope Operation
To setup the Analog channels
Vertical sensitivity Turn the large knob above the channel key to set the
sensitivity (volts/division) for the channel.
Vertical expansion The default mode for expanding the signal when you turn
the volts/division knob is vertical expansion about the ground level. To set the
expansion mode to expand about the center of the screen instead, press Expand
in the Utility Options menu and select Center.
Ground level The ground level of the signal for each displayed analog channel
is identified by the position of the
Channel position Turn the small channel position knob ( ) to move the
channel 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 center graticule and the ground level (
represents the voltage at the center graticule.
2 Press the Coupling
Coupling changes the channel's input coupling to either AC (alternating
current), DC (direct current), or Ground (hardware ground). AC coupling places
a 3.5 Hz high-pass filter in series with the input waveform that removes any DC
offset voltage from the waveform. When AC is selected, "AC" is illuminated on
the front panel next to the channel position knob ( ).
• DC coupling is useful for viewing waveforms as low as 0 Hz that do not
have large DC offsets.
• AC coupling is useful for viewing waveforms with large DC offsets, or with
slowing moving DC offsets.
• Ground coupling is useful for removing clutter on screen, estimating the
baseline noise contribution by the oscilloscope, and measuring the
difference between oscilloscope ground and device-under-test ground.
3 Press the BW Limit
Pressing the BW Limit softkey turns the bandwidth limit on or off for the selected
channel. When bandwidth limit is on, the maximum bandwidth for the channel
is approximately 20 MHz. For waveforms with frequencies below 20 MHz,
turning bandwidth limit on removes unwanted high frequency noise from the
waveform. Bandwidth limit also limits the trigger signal path if the channel you
are configuring is the trigger source.
When BW Limit is selected, "BW" is illuminated on the front panel next to the
channel position knob ( ).
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icon at the far-left side of the display.
softkey to select the input channel coupling.
softkey to turn on bandwidth limiting.
) icon. It also