Agilent Technologies 8564EC, Service Manual

Page: 141 / 512

Chapter 3 173
Manual Adjustment Procedures: 3335A Source not Available
3a . DC Log Amplifier Adjustments
10.If the signal is higher than expected (delta marker amplitude reads
greater than
−
38 dB) then adjust A4R544 for an even higher level
signal and press
CAL
and
ADJ CURR IF STATE
. Allow sufficient time
for the analyzer to complete the adjustment.
11.Repeat step 7 through step 10 .
A4 LOG Fidelity Adjustment
1. Press
LINE
to turn the spectrum analyzer off. Remove the spectrum
analyzer cover and place the spectrum analyzer in the service
position as illustrated in
Figure 3a-3 . See Figure 3a-4 for adjustment
location.
2. Connect the E4421B RF output to the spectrum analyzer 50
Ω
input.
Press
LINE
to turn the spectrum analyzer on.
3. On the spectrum analyzer, press
PRESET
,
CAL
,
IF ADJ ON OFF
(OFF),
and
ADJ CURR IF STATE
.
4. Set the spectrum analyzer controls as follows:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 MHz
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 MHz
Resolution bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 kHz
Reference level
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −
10 dBm
5. Set up an E4421B as follows:
Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 MHz
Amplitude
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −
10 dBm
Mod On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Off
6. On the spectrum analyzer, press
MKR
and
MARKER DELTA
.
7. Decrease the E4421B power to
−
26 dBm.
8. Calculate the error:
9. If the error is less than
±
0.2 dB, no adjustment is necessary.
10.Set the E4421B power to
−
10 dBm.
11.Adjust A4R531 (see Figure 3a-4 ) to read two times the error. For
example, if the calculated error is +0.75 dB, adjust A4R531 for a
delta marker amplitude reading of +1.5 dB. Press
CAL
and
ADJ CURR IF STATE
.
12.Repeat step 7 through step 11 .
Error delta marker reading 16 dB – =