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Section V
Model
654A
75Il
TO
SOil
CO
NVERTER
rHREADED
SLEEVE
hp
PARTND.
11
04
8-27604
r - - -
l
750'
43_20
±1"Io
I
/
BW
RI
/,{,
PART
NO.
757-
0
392
86.611
± 1"10
I/BW
R2
hp
PART NO.
069B-439B
500
Figure 5-7. Impedance
Converter
5-8
e.
Adjust the wave
analyzer
to the
same frequency as
the 654A
and
for
a
meter indication of between
-7dB and +3dB.
f. Adjust
control
level.
the
for
tracking
a meter
oscillator
SCALE OFFSET
indication
of
OdB reference
g.
Check the
654A
10dB attenuator
at each
position
by
decreasing
attenuation
on
the
external
attenuator as
attenuation
is increased
on
the 654A
attenuator.
at each position the tracking
oscillator
meter indication should be OdB, +1-0
.15dB.
h.
Check
the 654A 10dB attenuator at
the
following procedure.
I) Set the 654A to 10MHz.
10MHz using
2)
Repeat
steps
d, e and
f of
this paragraph.
3) Repeat step
g of
this paragraph for the +10
through -60dB position
of
the
654A attenuator.
4) Repeat
step g
for the
-70
and
-80
positions of
the 654A
attenuators
except that the tracking
oscillator
meter indication
for
these
two
positions should be OdB,
+1-
ldB
.
- - - - - NOTE - - - - -
This procedure,
so
far, has checked
only
one
side
of the
attenuator,
the following
step
describes how to
check
the
other
side
.
1.
Check
the
other side
of the
654A
10dB attenuator
at 300kHz
and 10MHz
by
interchanging the two
cables
connected to the
654A output
connectors
(i.e.
as
viewed in
Figure 5-6,
the
cable
terminated
in 75
ohms
is moved
with
the termination to the
right-hand
connec
tor
and
the
cable connected
to
the 75
ohm
to 50
ohm
impedanc
e
converter
is
mov ed with the converter to the left-hand con-
nector)
;
then repeat
steps
c through h
of
this
paragraph_
5-27. IdB-STEP ATIENUATOR CHECK.
- - - - - N O T E - - - - - -
See Paragraphs 5-24 and 5-25 before
making this
check.
a.
Conned
the
equipment
as in
Figure
5-6
with
the
1
d
B/step
e
xternal
allelluJtor connected directly
between
the 75
ohm
to
50 ohm
impedance
COIl-
verter and
31
2A
Wave
Analyzer.
b. Perform steps band c
of
Paragraph
5-26.
c.
Set the external attenuator to the -9dB
pOSi
tion
.
d. Perfonn
steps e
and f
of
Paragraph
5-26.
e. Check the 654A IdB step attenuator
at
each
position by decreasing attenuation on the
external
attenuator
as
attenuation
is increased
on
the
654A
attenuator; at each position the tracking
oscillator
meter indication should be OdB, +1-0.15dB.
f.
Repeat the check
with the 654A
and
wave
analyzer
set
to 10MHz to verify the attenuator
accuracy at high frequency.
------NOTE - - - - - -
This procedure,
so far.
has
checked
only
one side of
the
attenuator.
the following
s
tep
describes
remaining half.
how
to
check
the
g.
Check the
attenuator
other
at
side of
the 654A
300kHz
and
IdB
10MHz
step
by
interchanging the cables (as described in Paragraph
5-26
,
step i)
and
repeating
steps
b through f
of
this
paragraph (5-27).
5-28. BALANCE CHECKS.
5-29.
If the tolerances
given
in the following procedures
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