ADJUSTMENTS

519.LOG AMPLIFIER LOG AND LINEAR ADJUSTMENT(SERIAL PREFIX 22O8A)(Cont'd)

Set output level of signal generator for a digital voltmeter reading of 800 mV plus offset (algebraic sum)

flmY

Set Amplitude Scale to 10 dB/DIV and adjust A14R2 LOG LIN adjustment for a digital voltmeter reading of 800 mV plus offset.

Repeat step 14 to recheck the log fidelity.

Set the REF LEVEL dBm control to -50. Set Amplitude Scale to 1 dB/DIV.

Set the step attenuator to 0 dB and set output level of signal generator for a digital voltmeter reading of 700 mV (do not include offset).

Set the REF LEVEL dBm control to -90 and the step attenuator to 40 dB. Adjust A14R1,LOG GAIN adjustment for a digital voltmeter reading of 700 mY

Change REFERENCE LEVEL and step attenuator settings as shown in Table 5-8.Deviation from Reference should not exceed the given limits.

TABLE 5-8.LOG GAINADJUSTMENT LIMITS

Reference Level

Step Attenuator

Deviation From

(dBm)

Setting (dB)

Reference

 

 

 

-50

0

Reference (700 mV)

- 60

10

k30 mV

-70

20

+30 mV

-80

30

+30 mV

-90

40

*30 mV

 

 

 

Return the TEST-NORM switch on assembly A12 to the NORM position.