Performance
Check-2445A/2455A
Service
HORIZONTAL (cont)
4. Check Delay Jitter.
a.
Set:
TRACKING
A SEC/DIV
B SEC/DIV
BTRIG
Off
1 ms
500
ns
(knob out)
RUN
AFT
DLY
b. Connect Time-Mark Generator to the
CH
1 or X
input. Select 1-ms time markers from the Time-Mark
Generator.
c.
Align the intensified zones with
the
1 0th time marker
using the
A
REF
OR
DL Y
POS
and
A controls. Superim-
pose the zones to obtain a
At
readout display of 0.000
ms.
d.
Push
in
the SEC/DIV knob
and
adjust TRACE
SEP
to separate the traces.
e.
CHECK-For
0.8 divisions or less of horizontal jitter
on
the rising edge of both time markers.
5.
Check SEC/DIV VAR Range and Accuracy.
a.
Set:
A SEC/DIV
SEC/DIV
VAR
At
HOLDOFF
10
ms (knob
in)
In
detent
Off (press
and
release
to eliminate
At
readout)
BENDS A
b.
Select 10-ms time markers from the Time-Mark Gen-
erator
and
adJust
the Time-Mark Generator variable timing
control for exactly 1 time marker per division. Note the
variable timing % error
on
the Time-Mark Generator.
c. Adjust the SEC/DIV
VAR
control for a sweep-speed
readout
(on
bottom line of readout) of
20
ms
and
adjust
the Time-Mark Generator variable timing control for
exactly 2 time markers per division.
d.
CHECK-
The
Time-Mark Generator variable timing
%
of
error has changed 2% or less from the reading noted
in
part
b.
e.
Adjust the SEC/DIV
VAR
control fully CCW.
f.
CHECK-Sweep
speed readout displays 30.0 ms.
g. Set the Time-Mark Generator variable timing control
for exactly 3 time markers per division.
h.
CHECK-The
Time-Mark Generator variable timing
% of error has changed 2% or less from the reading noted
in
part
b.
Set SEC/DIV
VAR
to detent.
i.
Set:
SEC/DIV
VAR
A SEC/DIV
B SEC/DIV
At
B
TRIGGER
MODE
A
REF
OR
DLY
POS
CW
(in
detent)
50 ms
10
ms
(knob
in)
Off (DL Y readout)
RUN
AFT
DLY
Zero delay
NOTE
On
CTT instruments, rotate the
..::1
REF OR
DL
Y
POS
control for the specified
delay.
As
the con-
trol is rotated, the readout delay
value
will be fol-
lowed by the word
"SET", denoting the indirect
measurement mode. A few seconds after control
movement has stopped, the word
"SET" will
disappear and
the readout will display a direct
measurement from the
CTT.
j.
Repeat parts b through h for the B Sweep.
k.
Disconnect the test setup.
4.33
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