Tektronix 2445, Instruction Manual

Page: 111 / 351

Performance C h e c k -2 4 4 5 Service
X10 MAG
TRIGGER
MODE
SOURCE
COUPLING
SLOPE
LEVEL
B TRIG MODE
On (button in)
Off (DLY readout)
AUTO LVL
VERT
DC
+ (plus)
As required for a stable
display
RUN AFT DLY
b. Set the Time-Mark Generator for 20 ns markers.
c. Adjust the A REF OR DLY POS control for a readout
display of DLY 21.25 ns.
d. Adjust the Horizontal POSITION control CCW until
the cursor stops moving, then CW to display the leading
edge of the 2nd time marker near the graticule center. This
becomes the reference point for the following procedure.
e. Press and release the At button to obtain the At dis­
play and rotate the A control for a readout display of
At -2 1 .2 5 ns. If the time marks are not superimposed, ad­
just the A control to do so.
Delta Time Display Accuracy
Time-
Marker
Marker
Period
Super-
and A
B SEC/ imposed
SEC/DIV
DIV using the
Switch Switch A
(Delta)
Delta Time Readout
Setting Setting
Control Accuracy Limits
20 ns
1 nsa 1st — 19.25 ns to 20.25 ns
2nd —0.20 ns to 0.20 ns
3rd 19.25 ns to 20.25 ns
4th 39.70 ns to 40.30 ns
5th 59.60 ns to 60.40 ns
6th 79.55 ns to 80.45 ns
7th 99.50 ns to 100.50 ns
8th 119.45 ns to 120.55 ns
9th 139.40 ns to 140.60 ns
10th 159.30 ns to 160.70 ns
50 ns 1 nsa
1st -4 9 .3 ns to -5 0 .7 ns
3rd 49.3 ns to 50.7 ns
10th 398.3 ns to 401.70 ns
a10 ns with X10 MAG on (button in).
f. CHECK— At readout is within the limits listed in Table
4-8 for the 1st 20 ns time marker; then check that the 2nd
through 10th time markers are within the given limits as the
A control is rotated CW to superimpose each successive
time marker on the reference time marker.
k. CHECK— At readout is within the limits listed in Table
4-8 for the 1st 50 ns time marker; then check that the 3rd
and 10th time markers are within the given limits as the
A control is rotated CW to
superim pose e ach tim e m a rk er
on the reference time marker.
g. Set:
A SEC/DIV 50 ns
At Off (DLY readout)
h. Set the Time-Mark Generator for 50 ns time markers
and adjust the AREF OR DLY POS control for a readout
display of 53.2 ns.
l
. Set:
TRACKING/INDEP TRACKING (button in)
A SEC/DIV 0.1
fis
B SEC/DIV 10 ns (knob out)
X I0 MAG On (button in)
m. Select 0.1
(is
time markers from the Time-Mark
Generator.
i. Position the leading edge of the 1st time marker near
graticule center using the Horizontal POSITION control.
j. Press and release the At button to obtain a At display
and adjust the A control for a readout display of At
—53.2 ns. If the time markers are not superimposed, adjust
the A control to do so.
n. Adjust the A and AREF OR DLY POS controls for a At
readout display of At 800.0 ns.
o. Adjust the Horizontal POSITION control to align the
leading edge of the 2nd time marker on the A sweep with
the 2nd vertical graticule line.