
11. Down/Up Converter Adjustments
21.4
MHz
Gain
18.4
MHz
Null
Adjustment
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
~CENTER
FREQUENCY) 21.4 MHz,
CFREQUENCY
SPAN]
50
kHz,
fj’j]
10
kHz,
[REFERENCE LEVEL) -30
dBm.
Connect the tip of the active probe to
A4A6A2TP4.
On the
second spectrum analyzer, press
CREFERENCE
LEVEL] and use the
DATA knob to position the peak of the displayed 2 1.4 MHz signal
near the top CRT graticule line.
On the second spectrum analyzer, key in
(jj’
2
dB,
MARKER (PEAK SEARCH] and record the level of the displayed 21.4
MHz signal:
Signal level at
A4A6A2TP4:
dBm
On the second spectrum analyzer, key in MARKER [al,
~CENTER
FREQUENCY] 3 MHZ.
Connect the tip of the active probe to
A4A6A2Pl-9.
On the
second spectrum analyzer, key in MARKER [PEAK SEARCH] and
record the level of the displayed 3 MHz signal:
Signal level at A4A6A2Pl-9:
dB
The 3 MHz signal level at A4A6A2Pl-9 measured in step 12
should be 10.0
dB
f0.6
dB
lower than the 21.4 MHz signal level
at
A4A6A2TP4
measured in step 10. If not, change the value
of factory-select resistor
A4A6A2R33.
A 10% decrease in the
value
of
A4A6A2R33
increases the signal level at
A4A6A2Pl-9
by
approximately 0.6
dB.
Refer to Table 3-3 for the acceptable range
of values for
A4A6A2R33
and to
Table
3-4 for HP part numbers.
Set the spectrum analyzer LINE switch to STANDBY.
Remove
A4A6
Down/Up Converter Assembly from the two
extender boards and reinstall in the IF-Display Section.
Set the spectrum analyzer LINE switch to ON and press
C-1.
On the spectrum analyzer, key in [CENTER FREQUENCY) 100 MHz,
~FREQUENCY
SPAN_)
10
kHz,
(RES]
1
kHz,
[REFERENCE
LEVELS
-7
dBm,
and press the LIN pushbutton.
On the spectrum analyzer, key in MARKER (PEAK SEARCH),
MARKER
Ia],
(jj-
1 MHz.
Adjust A4A6AlR29 WIDE GAIN for a MKR A indication of 1.00 X,
aligning the two markers on the CRT display. See Figure 3-51 for
the adjustment location.
Disconnect the spectrum analyzer CAL OUTPUT from the RF
INPUT.
On the spectrum analyzer, key in (REFERENCE
LEVELI)
-70
dBm,
(jj)
1 kHz, MARKER (OFF).
On the second spectrum analyzer, key in
c-1,
[START
FREQ]
5
MHz,
CsTopFREQ)
50 MHz,
IjREs)
100
kHz.
3-102
Adjustments
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