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 .................................................... 15MHz
Span ................................................................................... 0
Resolution bandwidth ........................................... 300kHz
Reference level ...................................................... −10dBm
5. Set up an 3335A as follows:
Frequency ............................................................... 15MHz
Amplitude ............................................................. −10dBm
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.
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