User's Manual
Adlustnent 
Procedure 
- 
494ful4g4Ap 
Servtce 
Vot. 1
Flgure 
5-16. 100 
kHz 
over l0 kHz 
litter 
respona€.
(1) 
Set 
the, 
foltowing 
adjustments 
to  midrange:
R4025 on 
the 
VR 
2nd 
Fitter 
Select 
board, 
and 
R3OIO
'and 
R3025 
in 
the 
10Hz/100H2 
Bandpass 
Fitter
assembly.
(2) 
Install 
jumpers 
on 
J30i5, 
JgogS, and 
J3052 in
the 
10 
Hzll00 
Hz Fitter 
assembty 
(Figure 
5-ig).
(3) 
Apply 
the 
CAL 
OUT 
signat 
to th€ 
RF 
tNpUT, and
set 
the 
Spectrum 
Analyzer 
controls 
as follows:
FREQUENCY 
100 
MHz
FREQ 
SPAN/D|V 
100 
Hz
AUTO 
RESOLN 
Off
RESOLUTTON 
BANDWTDTH 
100 
Hz
VERT|CAL 
DTSPLAY 
2 
dB/DtV
REFERENCE 
LEVEL 
-20 
dBm
Throughout 
the 10 
Hz 
ftlter 
adiustment, 
set
the 
REFERENCE 
LEVEL 
as 
needed 
to main-
tain 
a 
7-division 
excursion 
of 
the 
display.
(4) 
Adjust 
R4025 
on 
the 
VR 
2nd 
Filter 
Set€ct board
(Figure 
5-17) 
for 
maximum 
signal 
amplitude.
(5) 
Set TIME/D|V 
to 
50 ms. 
(6) 
Adjust 
Rg0i0 in 
the
10 
Hzl100 Hz 
Bandpass 
Fitter 
assembty (Figure 
5-
18) 
for 
maximum 
signal 
amplitude.
0 
Adjust 
R3025 
in 
the 
10Hz/100H2 
Bandpass
Filter assembly 
for 
maximum 
signal 
amplitude.
(8) 
Remove 
the 
jumper 
from 
JO01S 
(1st 
stage 
of 
the
bandpass filter) 
in 
the 10 Hzl100 
Hz 
Bandpass 
Filter
assembly.
s-l6
(9) 
Adjust 
C1032 
in 
the 
loHz/lfi)Hz 
Bandpass
Filter 
assembly 
for 
maximum slgnal amplitude.
(10) 
Set the Spectrum Analyzer controls 
as 
follows:
FREQ 
SPAN/DIV 
'10 
Hz
RESOLUTION 
BANDWIDTH 10 
Hz
VERTTCAL 
DTSPLAY 
5 dB/DlV
T|ME/D|V 
AUTO
(11) 
Press 
(Blue-SHIFT> 
WIDE 
and select 
item
#3 
CTOGGLE 
EOS 
CORRECTTON MODE).
(12) 
Reset 
the 
CENTER 
FREQUENCY 
as necessary
to 
center 
the 
100 MHz 
calibrator signal, 
then set 
the
REFERENCE 
LEVEL for 
a seven-division 
excursion
of the display.
(13) 
Activate 
SAVE A. Store 
s€ttings 
in register 1
by 
pressing 
<Blue-SHIFT> 
STORE 
1.
(14) 
Set the Spectrum Analyzer controls as follows:
FREQ 
SPAN/DIV  100 
Hz
RESOLUTION 
BANDWIDTH 100 
Hz
VERTICAL DTSPLAY 
10 
dB/DlV
VIEW 
A 
Otr
(15) 
Store settings in register 2 
by 
pressing 
<Blue-
SHIFT> STORE 
2.
(16) 
Adjust C4015 in 
the 
10Hz/100H2 
Bandpass
Filter 
assembly 
for b€st 
symmetry.
(17) 
Press RECALL 
SETTINGS 
1.
(18) 
Adjust 
C4028 In 
the 
10Hz/100H2 
Bandpass
Filtsr 
assembly 
to 
match th€  trequency of 
th€ 
B
display to that 
of 
the sAVE 
A 
display.
(19) 
Repeat adiustment of 
C4015 
and 
C4028 to
eliminate 
interaction.
(20) 
Remove 
the 
jumper 
from 
J3038 
(2nd 
stage 
of
the 
bandpass filter) and 
install 
it 
on 
J3015 
in the
10 Hzl100 
Hz Bandpass Filter assembly.
(21) 
Press RECALL 
SETTINGS 
1.
(22) 
Adjust 
C4036 
in 
the 
10Hz/10OHz Bandpass
Filter assembly to  matoh 
th€ frequency of the 
B
display to 
that of 
the sAvE 
A 
display.
(23) 
Press RECALL 
SETTINGS 
2.
(24) 
Adjust 
C4045 
in 
the 
10 Hzl100 Hz Bandpass
Filter 
assembly 
for best symmetry.
(25) 
Repeat 
parts 
22  through  25 
to 
eliminate
interaction.
(26) 
Remove 
the 
jumper 
from 
J3052 
(3rd 
stage 
of
the 
bandpass filter) and 
install it on 
J3038 
in 
the
10 Hzll00 
Hz Bandpass Filter assembly.
(27) 
Press RECALL 
SETTINGS 
1.
(28) 
Adjust 
C4051 
in 
the 
10Hz/100H2 
Bandpass
Filter 
assembly 
to 
match 
the 
frequ€ncy 
of  the 
B
display to that 
of 
th€ SAVE 
A 
display.
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