Tektronix 1S1 Instruction Manual page 79

Calibration – Type 1S1
l. With the indicator oscilloscope Horizontal Position
control and Ext Horiz Input Variable control, position the
two dots to the 1-cm and 9-cm graticule lines as shown in
Fig. 5-16. This sets the external horizontal deflection factor to
1 volt/cm. Now, do not change the setting of the Ext
Horiz Input Variable control for the remainder of the cali-
bration procedure, or at least until the Type 1S1 TIMING
CAL adjustment has been checked.
m. Disconnect the patch cords that connect to the test
oscilloscope vertical input and to the indicator oscilloscope
Cal Out connector. Leave the patch cord connected between
the Type 1S1 HORIZ OUTPUT jack and the indicator oscil-
loscope Ext Horiz Input jack.
n. Reset the test oscilloscope Input Atten switch to 1.
o. Connect the time-mark generator Marker Out signal
through an adapter, a coax and the variable attenuator to
the SIGNAL IN connector of the Type 1S1.
p. Set the time-mark generator for a 1-µsec output signal.
q. Adjust the variable attenuator to produce approxi-
mately 2cm of vertical deflection on the indicator oscillo-
scope crt screen. (Increase the indicator oscilloscope intensity
if necessary.)
r. Reset the following Type 1S1 controls:
DISPLAY MODE
TRIGGER SOURCE
s. Trigger the display with the Type 1S1 TRIGGER SEN-
SITIVITY control.
t. Adjust the indicator oscilloscope Horizontal Position
control to position the start of the display to the left edge of
the graticule (see Fig. 5-17A).
u. Adjust the Type 1S1 SAMPLES/CM control for an ade-
quate display of the time-mark signal (see Fig. 5-17B). The
dots in the baseline should be as close together as possible
without reducing the display repetition rate far enough to
cause it to flicker.
v. Set the time-mark generator for a 5-µsec output signal.
w. Set the Type 1S1 TIME/CM switch to 5 µSEC. The
indicator oscilloscope Intensity control may require read-
justment for this slower ramp.
x. Adjust the Time Position FINE control to position one
of the 5-µsec markers on the 1-cm graticule line (see Fig.
5-17C).
y. Check for correct timing (1 marker/cm) over the center
8 cm (±0.08 cm) of the graticule. See Fig. 5-17D.
z. Adjust R335 (TIMING CAL) if the timing is not correct.
See Fig. 5-18 for the location of R335.
9. Adjust Comparator Level
a. Leave the time-mark signal connected to the SIGNAL
IN connector.
b. Install the 10X probe on the vertical input of the test
oscilloscope.
c. Reset the following test oscilloscope controls:
Time/Cm
Vc Range
Input Coupling
Millivolts/Cm
Millivolts/Cm Variable
5-16
NORMAL
INT +
.1 mSEC
0
Ac
2
Calib
Fig. 5-17. Typical indicator oscilloscope displays for setting up
sampling display and checking adjustment of R335 (TIMING CAL).