Tektronix T912 - Page 34

Performance
Check—T91
2
14.
Magnified
Sweep
Accuracy
a. Set;
X1-X10
X10 (fully
cw)
SEC/DIV
0.5
/js
b.
Set
time-mark
generator to 50
ns
(adjust CH
1
VOLTS/DIV,
INTENSITY, FOCUS,
and
POSITION
as
necessary for a
visible display),
NOTE
If you
cannot
obtain
a
stable display,
connect the
time-mark
generator
trigger
output to
the X (or EXT,
external
trigger)
connector
via a 50 0
cable
and a
50 O
termination.
Set SOURCE
to
EXT and adjust
LEVEL control
for
a
stable
display.
c. CHECK—
Magnified sweep accuracy
according to
Table
3-4:
one
or two time
marks, as
indicated,
within 5%
(0.4
div) over
center
eight divisions.
Exclude
thefirst 50 ns
after the
start
of the sweep;
(one
division for
0.5
ps
and
1
ps
settings), and
anything beyond
the 100th magnified
division.
Accuracy
specifications
apply for a
temperature
range
of
+20°
C to
+30°
C.
d. Return
X1-X10 to XI and
SOURCE
to INT.
Table
3-4
MAGNIFIED
SWEEP
TIMING
ACCURACY
SEC/DIV
Time-Mark CRT
Display
Switch
Setting
Generator Output
(Marker/Division)
.5
ps
50
nanoseconds 1
1
ps
.1
microsecond
1
.5
ms 50
microseconds
1
e. Set the
INTENSITY
control for
normal
brightness.
f. Set:
MODE
SINGLE SWP
STORE
Storage
(button
in)
ENHANCE
LEVEL
Fully ccw
SOURCE
LINE
LEVEL
Midrange (so
single
sweep
will trigger)
g.
Press
ERASE
and release;
press
MODE
switch to
RESET
position, then
let
it
return
to
SINGLE
SWP
position;
then
vertically
reposition
the trace.
Repeat
this
process
until
several traces are
stored
within the
center
6
X
8
division
area
of the
screen.
h.
CHECK—
That
single sweeps
store
without
breaks
greater
than 0.1
division over
the center
6X8
divisions of
the
screen.
16.
Enhanced
Writing
Rate
a.
Connect test
setup
as
shown
in Fig.
3-4.
b. Set
the
time-mark
generator for
10
ps.
c.
Set;
SEC/DIV
lOy/s
store
Nonstore
(button
out)
SOURCE
INT
MODE
AUTO
INTENSITY
Slightly
above
normal
brightness
level.
level
As
required
POSITION
(all)
As
required
15. Stored
Writing Rate
a.
Set
the
time-mark
generator for 0.1 ms.
b. Set:
SEC/DIV
0.1 ms
LEVEL
For triggered
sweep
c.
Turn the
X1-X10 control until the time
marks are
spaced 2.5
divisions
apart
(POSITION
as required).
d. Disconnect the
time-mark
generator, set
MODE to
AUTO, and
center the trace.
d.
Turn
the
X1-X10
control
until the
time marks
are
spaced
2.5
divisions
apart.
e.
Disconnect
the
time-mark
generator and
center the
trace.
f. Slowly
increase
the
INTENSITY
until the
trace begins
to
defocus
rapidly.
g.
Set:
MODE
SINGLE
SWP
STORE
Storage
(button
in)
SOURCE
LINE
3-8
REV. A APR
1977