Tektronix 1S1 Instruction Manual page 108

Amplitude Calibrator
Display
Millivolts/Cm
Input Atten
Millivolts/Cm Variable
Vc Range
Comparison Voltage
Input Coupling (Chan-
nel A)
Input Coupling (Chan-
nel B)
Pretrigger Pulse Generator
Repetition Rate
Range
Output Polarity
Variable
33. Check Tangential Noise
a. Test equipment setup is shown in Fig. 5-47.
b. Ccnnect the pretrigger pulse generator Pulse and
Pretrigger Output signals to the Type 1S1 as indicated in
Fig. 5-48.
c. Set the variable attenuator control to midrange.
d. Trigger the trace with the TRIGGER SENSITIVITY
control.
Fig. 5-48. Connections for applying pretrigger pulse generator
outputs to Type 1S1 for tangential noise check.
Off
A-Vc
10
1
Calib (at detent)
0
6.000
Dc
Gnd
Clockwise
10 Kc
+
Centered
e. Position the pulse display on the crt screen with the
pretrigger pulse generator Variable control and the Type
1S1 TIME POSITION and FINE controls.
f. Adjust the variable attenuator and the Type 1S1 VERT
POSITION controls to obtain a display similar to that shown
in Fig. 5-49A. Approximately 10% of the display dots should
Fig. 5-49. Typical indicator oscilloscope displays for setting
up and measuring tangential noise amplitude.
overlap the graticule centerline. (Effective trace width in
sampling is considered to be the width containing approxi-
mately 80% of the displayed dots.) This adjustment makes
the pulse amplitude equal to the noise amplitude (tangen-
tial sensitivity).
g. Leaving the variable attenuator at this setting, re-
move one of the 10X attenuators from the vertical signal
path.
h. Check that the display amplitude is 5cm or less with
the attenuator removed (Fig. 5-49B), indicating a noise
amplitude of 1 mv or less.
34. Check Baseline Shift
a. Disconnect the pulse signal from the SIGNAL IN con-
nector, but leave the triggering signal connected to the
Type 1S1 EXT TRIG connector.
Calibration – Type 1S1
5-45