ADJUSTMENTS

MODEL 8559A

ADJUSTMENTS

 

5-24. STEP GAIN ADJUSTMENTS (Cont'd)

 

PROCEDURE:

 

Set spectrum analyzer controls as follows:

 

FREQSPAN/DIV ..........................................................

lMHz

RESOLUTIONBW .........................................................

lMHz

INPUTATTEN .............................................................

10dB

REFLEVELdBm ...............................................................

0

Amplitudescale .........................................................

ldB/DIV

SWEEPTIME/DIV ........................................................

AUTO

SWEEPTRIGGER .....................................................

FREERUN

VIDEO FILTER .............................................................

MIN

Connect equipment as shown in Figure 5-10. Connect signal generator tuned to 321.4 MHz with approximately - 30 dBm output to one side of a 1 dB/step attenuator. Connect step attenuator output to AlOWl through adapter. Tune signal generator frequency for peak amplitude on display.

Set step attenuator to 12 dB and REF LEVEL FINE to - 12. Set signal generator level for a signal one division down from top graticule line.

Adjust A12R39 - 12 D until signal stops rising on display, then adjust A12R39 counterclockwise until signal drops approximately one third to one half of a division.

Set signal generator level so signal is one division down from top graticule line on display.

Set step attenuator to 0 dB and REF LEVEL FINE to 0.

Adjust A12R35 0 D adjustment for a signal level one division from top graticule line.

Set step attenuator to 12 dB and REF LEVEL FINE to - 12. DVM indication should be 700 +30 mV (offset). If offset is greater than +30 mV, repeat steps 3 through 8 until DVM indication is within limits.

Replace 1 dB/step attenuator with 10 dB/step attenuator set to 0 dB. Set REF LEVEL FINE control to 0.

Tune signal generator frequency for peak amplitude on the display (near 321.4 MHz).

Set signal generator level for a signal one division down from top graticule line. Set step attenuator to 10 dB and REF LEVEL dBm to - 10.

Adjust A12R6 10 D adjustment for signal level one division from top graticule line.

Set step attenuator to 20 dB and REF LEVEL dBm to - 20.

Adjust A12R21 20 D adjustment for signal level one division from top graticule line.

Set attenuator to 40 dB and REF LEVEL dBm to - 40.