Tektronix 1S1 Instruction Manual page 14

6. Adjust the oscilloscope Intensity control to display
a free-running trace of moderate brightness.
7. Adjust the DC OFFSET control to position the trace
near the horizontal centerline.
8. Adjust the oscilloscope External Horizontal Input Vari-
able control and Horizontal Position control to obtain ap-
proximately 10.2cm of horizontal deflection. If necessary,
set the Horizontal Display,switch to EXT X10.
9. Adjust the oscilloscope Focus and Astigmatism con-
trols for the best presentation. The dots should be small,
with equal vertical and horizontal dimensions.
10. Adjust the oscilloscope Trace Alignment control or
crt adjustment to align the trace with the horizontal center-
line.
11. Reset the Intensity control for a dim trace.
12. Remove the patch cord from the Type 1S1 HORIZ
OUTPUT jack and connect it between the oscilloscope Cali-
brator Output connector and the oscilloscope External
Horizontal Input jack. An adapter or a BNC/banana patch
cord may be required for the connection.
13. With the oscilloscope Horizontal Position control, posi-
tion the left dot to the 1-cm graticule line (see Fig. 2-2).
Fig. 2-2. Oscilloscope display for adjusting external horizontal
deflection factor ( 4%).
14. Adjust the oscilloscope External Horizontal Input
Variable control and Horizontal Position control to position
the right-hand dot to the 6-cm graticule line while the left
dot is at the 1-cm line.
15. Check that this adjustment is correct by positioning
the pair of dots to the 4-cm and 9-cm graticule lines. If there
is a difference in deflection, adjust the External Horizontal
Input Variable control for a compromise setting.
16. Remove the patch cord from the Calibrator Output
connector and reconnect it between the Type 1S1 HORIZ
OUTPUT jack and the oscilloscope External Horizontal In-
put jack.
17. With the oscilloscope Horizontal Position control,,
position the start of the trace at the left edge of the graticule.
18. Before making any accurate voltage measurements
from the display, check the vertical gain adjustment by ap-
Operating Instructions – Type 1S1
plying a signal from an accurate 50-ohm source, The oscillo-
scope calibrator cannot be used for this adjustment unless
it has an amplitude that is specified to be correct into 50
ohms.
19. Connect a positive-going pulse signal to the SIGNAL
IN connector through a 50-ohm coax cable and attenuators
as required. (A good signal for this purpose is a 600-mv 2-
nsec pulse with a repetition rate of about 70 kc, such as the
output pulse from a Tektronix Type 111 Pretrigger Pulse Gen-
erator applied through 20X attenuation). If the signal
amplitude is greater than 1 volt, peak to peak, attenuate it
with external attenuators. If the combined dc and peak ac
voltage is over 1 volt, ac-couple the signal with a coupling
capacitor at the SIGNAL IN connector.
20. Turn the TRIGGER SENSITIVITY control through its
range of rotation. Note that the display is free running
when the control is fully clockwise, that it is triggered when
the control is approximately midrange, and that the dis-
play is held off when the control is turned fully counter-
clockwise. (It may be necessary to increase the intensity
to view the triggered display.)
21. Set the TRIGGER SENSITIVITY control for a stable
triggered display.
Fig. 2-3. Typical oscilloscope display illustrating time magnification
of the display. Expansion takes place about the left edge of the screen.
2-5