Front-Panel Controls 2
6000 Series Oscilloscope User’s Guide 85
2Press the channel’s on/off key, then press the Coupling softkey
to select the input channel coupling.
Coupling changes the channel's input coupling to either AC
(alternating current) or DC (direct current). 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 coup ling is use ful fo r view ing w avefor ms as low as 0 Hz
that do not have large DC offsets.
AC coupling is useful for viewing waveforms with large DC
offsets. When AC coupling is chosen, you cannot select
50 mode. This is done to prevent damage to the
oscilloscope.
Note that Channel Coupling is independent of Trigger Coupling.
To change Trigger coupling see page 133.
3Press the Imped (impedance) softkey.
The analog channel input impedance can be set to either
1MOhm or 50 Ohm by pressing the Imped softkey.
Measurement Hints
If the channel is DC coupled, you can quickly measure the DC component of the
signal by simply noting its distance from the ground symbol.
If the channel is AC coupled, the DC component of the signal is removed, allowing
you to use greater sensitivity to display the AC component of the signal.
NOTE The input impedance of the MSO/DSO6012A and MSO/DSO6014A/L
(100MHz bandwidth) oscilloscope is fixed at 1 M. Therefore, the
impedance selection is not available on these models.
When you connect an AutoProbe, self-sensing probe, or a compatible
InfiniiMax probe, the oscilloscope will automatically configure the
oscilloscope to the correct impedance.