Performance Check-2445A/2455A Service
c.
Set
the generator output level for a 6-division display
at the reference frequency, then change the generator out-
put to 100 MHz for the 2445A
or
to 200 MHz for the
2455A.
d.
CHECK-Signal display amplitude is 4.25 divisions
or greater while sweeping the generator frequency from
100 MHz to 150 MHz for the 2445A or from 200 MHz to
250 MHz for the 2455A.
e.
Set the VOL TS/DIV to 0.5 V
and
repeat parts c
and
d.
f.
Set
the VOLTS/DIV to 1 V
and
the generator output
level
for a 4-division display at the reference frequency,
then change the generator frequency to 100 MHz for the
2445A or to 200 MHz for the 2455A.
g.
CHECK-Signal display amplitude is 2.82 divisions
or greater while sweeping the generator frequency from
100 MHz to 150 MHz for the 2445A or from 200 MHz to
250 MHz for the 2455A.
h.
Move the signal to
CH
2
OR
X input connector
and
set the VERTICAL MODE to disable
CH
1
and
display
CH
2.
i.
CHECK-Repeat parts c through g for
CH
2.
j. Set the VERTICAL MODE to display
CH
3 only.
k.
Attach the standard-accessory 1
OX
probe (supplied
with the instrument) to the
CH
3 input connector
and
the
probe tip to the CALIBRATOR terminal.
I.
Set
the SEC/DIV (knob
in)
to 1 ms.
m. Adjust probe compensation for the best flat top
on
the square-wave signal display.
n. Disconnect the probe tip from the CALIBRATOR ter-
minal. Remove the grabber tip
from the probe, unscrew
and
remove the plastic barrel,
and
connect the probe to
the output
of
the Primary Sine-Wave Generator via a BNC
female-to-BNC female and a subminiature probe-tip-to-
BNC
feed-through termination.
o. Set the SEC/DIV to 50
µS
(knob
in)
.
4-12
p.
Set the generator output for a 4-division display at
the reference frequency, then change the generator fre-
quency to 100
MHz
for 2445A or to 200 MHz for the
2455A.
q.
CHECK-Signal display amplitude
is
2.82 divisions
or greater while sweeping the generator frequency from
100 MHz to 150
MHz
for the 2445A or from 200 MHz to
250 MHz for the 2455A.
r. Move the signal to
CH
4 and set the VERTICAL
MODE to display
CH
4 only.
s.
CHECK-Repeat parts k through q for
CH
4.
t.
Disconnect the test setup.
6. Check Common Mode Rejection Ratio (CMRR).
a. Set:
NOTE
Select channels to
set
VOL TS/DIV.
VOLTS/DIV
CH
1
and
CH
2
10mV
CH
1
and
CH
2
VAR
In
detent
VERTICAL
CH
1,
ADD,
and
INVERT
On
CH
2,
CH
3,
and
CH
4 Off
Input Coupling
CH
1
and
CH
2
HORIZONTAL
A SEC/DIV
TRIGGER
SOURCE
1
Mn
DC
50
µs (knob
in)
CH
1
b.
Connect a reference frequency signal from the Pri-
mary Leveled Sine-Wave Generator to the
CH
1
OR
X
and
CH
2 input connectors via a 50 n
BNC
cable, a
5X
attenuator,
and
a Dual-Input Coupler.
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