8. First LO Distribution Amplifier Adjustment

Assembly Adjusted

Al4 Frequency Control Assembly

Related Performance Test

First LO OUTPUT Amplitude

Description

The gate bias for the A7 LO Distribution Amplifier is adjusted to the value specified on A7. LO AMPTD is adjusted so that the LO SENSE voltage is 6 mV more negative than the value specified on the A7 LODA label.

M E A S U R I N G R E C E I V E R

SPECTRUM

 

 

 

ANALYZER

 

 

 

 

 

 

 

DVM T E S T L E A D S

D I G I T A L V O L T M E T E R

SKI10

Figure 2-11. First LO Distribution Amplifier Adjustment Setup

Equipment

Measuring Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 8902A

DVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3456A

Power Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 8485A

DVMTest Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 34118A

Adapters

Type N (f) to APC (m) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1250-1750

Procedure

1.Set the HP 8560A (LINE) switch off and disconnect the line cord. Remove the cover and fold down the Al5 RF and Al4 Frequency Control assemblies. Reconnect the line cord.

2.Remove the 500 termination from the 1ST LO OUTPUT.

3.Connect the positive lead of the DVM probe to pin 15 of A14J18. Connect the DVM ground lead to pin 6 of A14J18. See Figure 2-11.

2-40 Adjustment Procedures