Agilent Technologies 8564EC, Service Manual

Page: 102 / 512

Chapter 3 125
Manual Adjustment Procedures
3 . DC Log Amplifier Adjustments
3. Press
PRESET
,
CAL
,
IF ADJ ON OFF
(OFF),
ADJ CURR IF
STATE
.
4. Set the spectrum analyzer controls as follows:
Center frequency .................................................... 15 MHz
Span ................................................................................... 0
Resolution bandwidth ........................................... 300 kHz
Reference level ......................................................
−
10 dBm
5. Set up an 3335A as follows:
Frequency ............................................................... 15 MHz
Amplitude .............................................................
−
10 dBm
6. Press
MKR
,
MARKER DELTA
on the spectrum analyzer.
7. Decrease the 3335A power to
−
26 dBm.
8. Calculate the error: EQUATION {\rm Error} = {\rm delta\ marker\
reading}-{\rm 16\ dB} EQUATION.
9. If the error is less than
±
0.2 dB, no adjustment is necessary.
10.Set the 3335A power to
−
10 dBm.
11.Adjust A4R531 (see Figure 3-10, “DC Log Adjustment Locations,” ) 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
,
ADJ CURR IF STATE
.
12.Repeat steps 7 through 11.