Calibration—475
29. Check Bandwidth Limit Operation
a. Connect a 6 division display of a 50 kHz signal to the
CH 1 input.
b. Check frequency is 20 MHz, within 5 MHz, when
display is reduced to 4.2 divisions.
TRIGGER SYSTEM CALIBRATION
30. Adjust A and B Trigger Sensitivity
a. VOLTS/DIV to 0.1 V,
A SOURCE to EXT,
A COUPLING to AC.
b. Connect the Medium-Frequency Constant-Amplitude
Signal Generator (Type 191) to the A and B External
Trigger inputs via a 50 £2 5 ns GR cable, 50 £2 Signal
Pickoff Unit, GR-to-BNC adapter, X10 attenuator, 50 £2
termination, and a dual input coupler.
c. Connect the 10% BNC output of the Signal Pickoff
Unit to both channel inputs via a terminated dual input
coupler.
d. ADJUST—A and B Sensitivity, R565, R785, to just
obtain a stable display with a 0.35 division, 350 kHz signal.
31. Adjust Trigger Centering and Symmetry
a. VOLTS/DIV to 50 mV,
SOURCE to NORM,
T IM E /D IV to 10ms.
b. Position a 2 division display of 350 kHz signal to the
center horizontal line.
c. ADJUST—B Trigger Symmetry, R547, so trigger point
is the same in both slopes.
d. ADJUST—B Trigger Center, R543, for a triggering
point at graticule center.
e. ADJUST—A Trigger Symmetry, R767, so triggering
point is the same in both slopes.
f. ADJUST—A Trigger Center, R754, for triggering point
at graticule center.
32. Adjust A Trigger DC Balance
a. A COUPLING to DC,
A SOURCE to NORM,
A LEVEL to 0.
b. Use a 0.3 division display.
c. ADJUST—Normal Trigger DC Balance, R425, to
obtain a stable display in both slopes.
d. Change A SOURCE to CH 1.
e. ADJUST—CH 1 Trigger DC Balance, R403, to obtain
a stable display in both slopes.
f. VERT MODE to CH 2,
A SOURCE to CH 2.
g. Check for stable display in both slopes.
33. Check B Trigger DC Balance
a. B COUPLING to DC,
B SOURCE to NORM,
B LEVEL to 0,
VERT MODE to CH 1.
b. Use a 0.3 division display.
c. Check for stable display in both slopes.
d. Set B SOURCE to CH 1 and repeat part c.
e. Set B SOURCE to CH 2, VERT MODE to CH 2, and
repeat part c.
5-18
®
To Next Page
Loading...
General
