16.Use a DVM to monitor the voltage at A14J18 pin 4. The voltage should measure approximately -8.45 Vdc.

17.Set the spectrum analyzer sweep time to 100 ms. The voltage at J18 pin 4 should measure approximately -4.21 Vdc.

18.Set the spectrum analyzer sweep time to 200 ms. The voltage at J18 pin 4 should measure approximately -2.1 Vdc.

19.The analog switches and comparators should be set as listed in Table 11-16.

20.Check that U312D opens when the sweep time is set to 2 seconds.

21.Check that U312B and U312C close when the sweep time is set to 20 seconds.

Table 11-16. Settings for Switches and Comparators

Sweep Time

Switch

Switch

Switch

Comparator

Comparator

 

U312B

U312C

U312D

U319A Pin 1

U319B Pin 7

 

 

 

 

 

 

200 ms

Open

Open

Closed

High

High

2 s

Open

Open

Open

High

High

20 s

Closed

Closed

Open

High

High

 

 

 

 

 

 

First LO Span Problems (Multiband Sweeps)

During multiband sweeps, the sweep ramp at A14J15 pin 15 should go from 0 V to +lO V for each band or portions of a band covered. See function block A of Al4 frequency control schematic in the HP 8560 E-Series Spectrum Analyzers Component Level Information binder. However, the scan ramp at A14U325A pin 1 is scaled according to the percentage of the total span that the band is covering. See function block B of Al4 schematic. Also, the sum of the individual ramps is 10 V. Figure 11-9 illustrates both sweep and the scan ramp for a 0 GHz to 13.2 GHz span with instrument preset conditions.

Synthesizer Section 11-41

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Agilent Technologies 856290216 First LO Span Problems Multiband Sweeps, Settings for Switches and Comparators