MODEL8559A

ADJUSTMENTS

ADJUSTMENTS

5-28. FREQUENCY RESPONSE ADJUSTMENTS

REFERENCE:

A3, A4, AS, A6, and A12 Schematics

NOTE

Perform CAL OUTPUT and REF LEVEL CAL adjustments (5-29)before proceeding with frequency response adjustments.

DESCRIPTION:

Frequency Response (flatness) is adjusted in six parts corresponding to the six harmonic bands of the analyzer. In each band, the analyzer is swept-tuned with a tracking signal source comprising a sweep oscillator and synchronizer. The sweep oscillator is tuned with an external sweep ramp generated by scaling the analyzer sweep output (AUX D) with a special tuning voltage circuit. This provides synchronizationof the sweeps of the two instruments (sweep oscillator and analyzer), thus providing phase-lock of the two instruments. Each of the bands is adjusted for optimum flatness and all bands are adjusted for equal amplitudes.

SWEEP

RF

 

OSCILLATOR

PLUG- IN

SYNCHRONIZER

D l SPLAY

1 ASSEMBLY 1CRYSTAL

1DETECTOR

ADAPTER

SPECTRUM

ANALYZER

0 0 0 0 o...

ADAPTER

METER

I ATTENUATOR '

L-----------4

POWER

! ADAPTER SENSOR

 

TUN lNG

I

-----0-------J

 

VOLTAGE

L----

 

C I R C U I T

ADAPTER POWER

 

( F I G U R E 517)

O V TO t 1 0 V

- 5 V TO +5V

SENSOR

-

 

FIGURE5-16,FREQUENCYRESPONSEADJUSTMENTSTESTSETUP