Model 3580A
ADJUSTMENT
PROCEDURES
Section V
k. Center the following pots:
A4R7, A4R8, A4R9,
A4Rl0,
A13R3 and
Al3R4.
1.
Reposition the following front panel controls:
INPUT SENSITIVITY
...............
CAL
SWEEP
MODE
.....................
REP
NOTE
If
the peak
of
the waveform
is
beyond display
limits, slightly readjust
A/3R3
or
A13R4
to
bring it into
view.
m.
Alternately switch between the
LOG
1 dB/DIV and
LOG
10
dB/DIV AMPLITUDE
MODEs
and adjust A4R8
(DETECTOR GAIN ADJ.) until the peak amplitude
of
both waveforms
is
equal.
n.
Alternately switch between the
LOG
10 dB/DIV and
LINEAR AMPLITUDE
MODEs
and adjust A4R6 (LINEAR
GAIN
ADJ.) until the peak amplitude of both waveforms
is
equal.
o.
Repeat Steps m and n until the peak amplitude
of
all
three waveforms
is
equal.
p.
Reposition the following front panel control:
AMPLITUDE
MODE
.......
LOG
10
dB/DIV
Press
and hold the DISPLAY-CLEAR WRITE button to
obtain a
base
line trace. Press the DISPLAY-STORE button
to store the base line trace. Release the CLEAR WRITE
button.
q.
Adjust
Al3R3
(VERTICAL GAIN ADJ.) and
Al3R4
(VERTICAL ZERO ADJ.) for a full scale and base line
screen display (waveform peak at 0
dB
and base line at
- 100 dB). Press and release the DISPLAY-STORE button.
NOTE
There may be some non-symmetry
in
the
bottom corners
of
the CRT display.
Use
the
center portion
of
the
base
line
trace
for the
above calibration.
r.
Reposition the following front panel controls:
INPUT SENSITIVITY . . . . . . . . . . . . - 20
dB
s.
Adjust the frequency synthesizer output level
to
- 80
dBV
for standard instruments or - 80 dBm 900 Q for
instruments equipped with Option 002.
See
Table 5-14 for
proper level setting
of
source.
t. Adjust A4R7 (LOG GAIN ADJ.)
so
display peak
is
at
the proper level. (- 60
dB
graticule ± 1
dB
on CRT display,
since full scale equals - 20 dB).
NOTE
This
is
a very low level
signal.
Always slide the
cover shield over the
AS
assembly after making
an
adjustment; then verify the results.
u. Increase the signal level back
to
full scale
(-
20 dBV
for standard instruments or - 20
dBm
900 Q for Option
002) and adjust A4R8 (DETECTOR GAIN ADJ.) for a full
scale (0
dB)
indication on the display.
v.
Repeat Steps
r,
s,
t, and u until the O
dB
and-60
dB
points
on
the display are calibrated properly.
w.
Alternate the input signal level between - 80 dBV
and - 60
dBV
(-
80
dBm
to
-
60
dBm
900 Q for Option
002).
See
Table 5-14 for proper level. The indication should
fall on the - 60
dB
and -
40
dB
(± I dB) graticule lines
of
the display.
If
not, adjust
A4Rl0
(BOTTOM END LINE-
ARITY ADJ.)
to
bring these two points
as
close into
tolerance
as
possilbe.
x. Alternate the input signal level between - 20 dBV and
- 40 dBV
(-
20 dBm
to
-
40
dBm, 900
fl
for Option 002).
See
Table 5-14 for proper level setting. These levels should
give
0
dB
and - 20
dB
(± 1
dB}
indications on the display.
If
not, adjust A4R9 (TOP END LINEARITY ADJ.) to
bring these two points
as
close into calibration
as
possible.
y. Adjust the input signal level to - 20 dBV (- 20 dBm,
900 Q for Option 002). Switch the AMPLITUDE MODE
pushbuttons between LOG 10 dB/DIV and LOG I dB/DIV.
Adjust A4R8 (DETECTOR GAIN ADJ.) or A4R7 (LOG
GAIN ADJ.) to make the levels for the two AMPLITUDE
MODE
settings equal.
z. Reposition the following front panel controls:
AMPLITUDE
MODE
.......
LOG
10 dB/DIV
aa. Step the input signal level in 10
dB
steps from a full
scale 0
dB
indication (- 20
dBV
or - 20 dBm 900 Q input
signal}
to a - 60
dB
indication
(-
80
dBV
or - 80
dBm
900 Q
input signal). The display should fall within ± 2
dB
of
the
proper graticule marking to meet specifications.
NOTE
Remember to position the inner circuit board
shield over
A2-A5
when making low level
measurements.
ab.
Repeat Steps r thru
aa
to bring the log amplifier
into the desired test limits.
ac. Adjust the input signal level
to
- 20
dBV
(Instru-
ments with Option 002 should also have this same input
level.)
5-23
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