Setting The Input Coupling; How To Set The Vzr (Vertical Zero Reference) - Tektronix 7D20 Operator's Manual

SETTING THE INPUT COUPLING
The 7D20 allows three choices for setting the input coupling .
Press
Remarks
AC DC
These keys select the input coupling for CH 1 . Initialization sets the
GND
7D20 for AC coupling so the AC key is illuminated when you begin.
Alternately press these keys and notice that the pressed key
illuminates and the previously illuminated key extinguishes. These
keys are mutually exclusive so only one can be selected at a time .
Notice too as you alternately press these keys, the effect that each
has on the displayed waveform . The next exercise shows how to use
GND input coupling to set the VZR (vertical zero referencel.
HOW TO SET THE VZR (Vertical Zero Reference)
The 7D20 uses cursors to make measurements on the waveforms . Cursor 1 is
always on but cursor 2 can be turned off or on as needed . In order for the cursors to
be accurate they must be referenced to ground or zero volts. This is called the
vertical (zero) reference level, VZR. The VZR readout indicates where the zero level
is in divisions from center screen .
Upon initialization, the VZR is established to be the center of the 7D20 display . You
can change this approximately 5 divisions (plus or minus) from the center position
as shown below.
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