Tektronix 222 Operator's Manual page 81

Section 5-222 DSO Operators
SECTION 5
MAKING MEASUREMENTS
5.1
SIGNAL TRACING WITH AUTO SETUP
The AUTO SETUP feature of the 222 Oscilloscope is very useful for
getting a quick setup to view unknown signals at the probe tips of the
two vertical channels. Pressing the
button performs many func-
tions for the user. It sets the vertical and horizontal scaling to display
the signal with several divisions of amplitude and 1 to 5 waveform
periods if possible. The trigger peak values are determined, and the
LEVEL control is set to the midpoint. The traces are positioned verti-
cally to provide an on-screen display. The Trigger MODE is set to
AUTO LVL and the Trigger SOURCE is set to VERT MODE. Both probe
tips are checked for a signal. If either channel display is off, it will be
turned on if a signal is found. If a signal is not found on either of the
probes, only the Channel 1 trace is turned on. (See Section
6,
para.
6.1
for a complete list of the default control settings.)
To use the auto setup feature for signal tracing, connect the probe tip
to the test point for the unknown signal. Then just press the AUTO
SETUP button. If a signal is applied to both probes, both channels will
be auto set vertically; only the trigger channel will be auto set hori-
zontally. If both signals are time related, both waveform displays will
be stable.
5.2
GRATICULE MEASUREMENTS
The graticule is internally marked on the crt face to provide parallax-
free viewing. The graticule has eight vertical and ten horizontal major
divisions. Major divisions are further divided into five sub-divisions of
0.2 division each, marked along the center vertical and horizontal
graticule lines. Two dotted graticule lines mark the 10% and 90%
points of a six-division signal. These lines aid the user in making
rise- and fall-time measurements. Vertical deflection factors and
horizontal timing are calibrated to the crt graticule for making
accurate measurements. The VOLTS/DIV and SECIDIV settings are